CveMateVulnerability intelligence

Sigstore vulnerabilities, page 2

39 vulnerabilities

Known vulnerabilities in Sigstore products, newest first, with CVSS severity, EPSS, KEV listings and ransomware use, across 13 products.

CVE-2026-31830RubyGemssigstore+27mo ago10-03-2026 21:46

sigstore-ruby is a pure Ruby implementation of the sigstore verify command from the sigstore/cosign project. Prior to 0.2.3, Sigstore::Verifier#verify does not propagate the VerificationFailure returned by verify_in_toto when the artifact digest does not match the digest in the in-toto attestation subject. As a result, verification of DSSE bundles containing in-toto statements returns VerificationSuccess regardless of whether the artifact matches the attested subject. This vulnerability is fixed in 0.2.3.CVE-2026-39984chainguardaactl+2156mo ago14-04-2026 23:41

Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Versions 2.0.5 and below contain an authorization bypass vulnerability in the VerifyTimestampResponse function. VerifyTimestampResponse correctly verifies the certificate chain signature, but the TSA-specific constraint checks in VerifyLeafCert uses the first non-CA certificate from the PKCS#7 certificate bag instead of the leaf certificate from the verified chain. An attacker can exploit this by prepending a forged certificate to the certificate bag while the message is signed with an authorized key, causing the library to validate the signature against one certificate but perform authorization checks against another. This vulnerability only affects users of the timestamp-authority/v2/pkg/verification package and does not affect the timestamp-authority service itself or sigstore-go. The issue has been fixed in version 2.0.6.CVE-2026-39395chainguardaactl+1636mo ago07-04-2026 20:06

Cosign provides code signing and transparency for containers and binaries. Prior to 3.0.6 and 2.6.3, cosign verify-blob-attestation may erroneously report a "Verified OK" result for attestations with malformed payloads or mismatched predicate types. For old-format bundles and detached signatures, this was due to a logic flaw in the error handling of the predicate type validation. For new-format bundles, the predicate type validation was bypassed completely. This vulnerability is fixed in 3.0.6 and 2.6.3.CVE-2026-22772chainguardaactl+919mo ago12-01-2026 20:58

Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio's metaRegex() function uses unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF. This vulnerability is fixed in 1.8.5.CVE-2026-22703chainguardaactl+1369mo ago10-01-2026 06:11

Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.CVE-2026-44309chainguardcg+45mo ago15-05-2026 16:22

Gitsign is a keyless Sigstore to signing tool for Git commits with your a GitHub / OIDC identity. Prior to 0.16.0, gitsign verify and gitsign verify-tag re-encode commit/tag objects through go-git's EncodeWithoutSignature before checking the signature, instead of verifying against the raw git object bytes. For malformed objects with duplicate tree headers, git-core and go-git parse different trees: git-core uses the first, go-git uses the second. A signature crafted over the go-git-normalized form (second tree) passes gitsign verify while git-core resolves the commit to a completely different tree. This breaks the invariant that a verified signature, the commit semantics git-core presents to users, and the object hash logged in Rekor all refer to the same content. This vulnerability is fixed in 0.16.0.CVE-2026-44310chainguardcg+45mo ago15-05-2026 16:17

Gitsign is a keyless Sigstore to signing tool for Git commits with your a GitHub / OIDC identity. From 0.4.0 to before 0.15.0, CertVerifier.Verify() in pkg/git/verifier.go unconditionally dereferences certs[0] after sd.GetCertificates() without checking the slice length. A CMS/PKCS7 signed message with an empty certificate set is a structurally valid DER payload; GetCertificates() returns an empty slice with no error, causing an immediate index-out-of-range panic. On the gitsign --verify code path (the GPG-compatible mode invoked by git verify-commit), the panic is silently recovered by internal/io/streams.go's Wrap() function, which returns nil instead of an error. main.go then exits with code 0, causing exit-code-only verification callers to interpret the failed verification as success. This vulnerability is fixed in 0.15.0.CVE-2026-24117chainguardaactl+1739mo ago22-01-2026 22:05

Rekor is a software supply chain transparency log. In versions 1.4.3 and below, attackers can trigger SSRF to arbitrary internal services because /api/v1/index/retrieve supports retrieving a public key via user-provided URL. Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF. The issue has been fixed in version 1.5.0. To workaround this issue, disable the search endpoint with --enable_retrieve_api=false.CVE-2026-24408linuxfoundationsigstore-python+38mo ago26-01-2026 22:21

sigstore-python is a Python tool for generating and verifying Sigstore signatures. Prior to version 4.2.0, the sigstore-python OAuth authentication flow is susceptible to Cross-Site Request Forgery. `_OAuthSession` creates a unique "state" and sends it as a parameter in the authentication request but the "state" in the server response seems not not be cross-checked with this value. Version 4.2.0 contains a patch for the issue.CVE-2026-24122chainguardaactl+1618mo ago19-02-2026 22:27

Cosign provides code signing and transparency for containers and binaries. In versions 3.0.4 and below, an issuing certificate with a validity that expires before the leaf certificate will be considered valid during verification even if the provided timestamp would mean the issuing certificate should be considered expired. When verifying artifact signatures using a certificate, Cosign first verifies the certificate chain using the leaf certificate's "not before" timestamp and later checks expiry of the leaf certificate using either a signed timestamp provided by the Rekor transparency log or from a timestamp authority, or using the current time. The root and all issuing certificates are assumed to be valid during the leaf certificate's validity. There is no impact to users of the public Sigstore infrastructure. This may affect private deployments with customized PKIs. This issue has been fixed in version 3.0.5.CVE-2026-24137chainguardaactl+2629mo ago23-01-2026 00:04

sigstore framework is a common go library shared across sigstore services and clients. In versions 1.10.3 and below, the legacy TUF client (pkg/tuf/client.go) supports caching target files to disk. It constructs a filesystem path by joining a cache base directory with a target name sourced from signed target metadata; however, it does not validate that the resulting path stays within the cache base directory. A malicious TUF repository can trigger arbitrary file overwriting, limited to the permissions that the calling process has. Note that this should only affect clients that are directly using the TUF client in sigstore/sigstore or are using an older version of Cosign. Public Sigstore deployment users are unaffected, as TUF metadata is validated by a quorum of trusted collaborators. This issue has been fixed in version 1.10.4. As a workaround, users can disable disk caching for the legacy client by setting SIGSTORE_NO_CACHE=true in the environment, migrate to https://github.com/sigstore/sigstore-go/tree/main/pkg/tuf, or upgrade to the latest sigstore/sigstore release.CVE-2026-49834chainguardaactl+2053mo ago17-07-2026 19:20

sigstore-go is a Go library for Sigstore signing and verification. Prior to 1.2.0, a verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) counts verified witnesses per entry or per validation path rather than per log authority, allowing a single compromised transparency log or CT log to satisfy multi-log threshold requirements and defeat the multi-log policy. This issue is fixed in version 1.2.0.CVE-2026-49835chainguardaactl+2193mo ago17-07-2026 18:16

Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Prior to 2.1.0, the global wrapMetrics middleware records raw HTTP request path r.URL.Path and raw HTTP request method r.Method as Prometheus labels for latency and request count metric vectors before routing, allowing an unauthenticated remote attacker to issue requests with random paths such as /api/v1/timestamp/<uuid> or random HTTP methods and create unbounded permanent time-series entries that exhaust memory. This issue is fixed in version 2.1.0.CVE-2026-49478chainguardaactl+1662mo ago13-08-2026 13:08

Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Versions through 1.8.5 improperly follow cross-host redirects and attach Kubernetes ServiceAccount tokens during OIDC discovery, allowing a malicious or compromised issuer to perform blind SSRF, substitute and cache malicious JWKS keys, or disclose ServiceAccount tokens to external hosts. Version 1.8.6 blocks cross-host redirects, restricts token injection, and restricts local token loading. No known workarounds are available.CVE-2026-23831chainguardaactl+1739mo ago22-01-2026 21:26

Rekor is a software supply chain transparency log. In versions 1.4.3 and below, the entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message, causing nil Pointer Dereference. Function validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload. A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal. This issue has been fixed in version 1.5.0.CVE-2023-47122github.com/sigstoregitsign+12y ago10-11-2023 21:33

Gitsign is software for keyless Git signing using Sigstore. In versions of gitsign starting with 0.6.0 and prior to 0.8.0, Rekor public keys were fetched via the Rekor API, instead of through the local TUF client. If the upstream Rekor server happened to be compromised, gitsign clients could potentially be tricked into trusting incorrect signatures. There is no known compromise the default public good instance (`rekor.sigstore.dev`) - anyone using this instance is unaffected. This issue was fixed in v0.8.0. No known workarounds are available.CVE-2023-46737chainguardaactl+352y ago07-11-2023 17:30

Cosign is a sigstore signing tool for OCI containers. Cosign is susceptible to a denial of service by an attacker controlled registry. An attacker who controls a remote registry can return a high number of attestations and/or signatures to Cosign and cause Cosign to enter a long loop resulting in an endless data attack. The root cause is that Cosign loops through all attestations fetched from the remote registry in pkg/cosign.FetchAttestations. The attacker needs to compromise the registry or make a request to a registry they control. When doing so, the attacker must return a high number of attestations in the response to Cosign. The result will be that the attacker can cause Cosign to go into a long or infinite loop that will prevent other users from verifying their data. In Kyvernos case, an attacker whose privileges are limited to making requests to the cluster can make a request with an image reference to their own registry, trigger the infinite loop and deny other users from completing their admission requests. Alternatively, the attacker can obtain control of the registry used by an organization and return a high number of attestations instead the expected number of attestations. The issue can be mitigated rather simply by setting a limit to the limit of attestations that Cosign will loop through. The limit does not need to be high to be within the vast majority of use cases and still prevent the endless data attack. This issue has been patched in version 2.2.1 and users are advised to upgrade.CVE-2023-30551chainguardaactl+253y ago08-05-2023 15:52

Rekor is an open source software supply chain transparency log. Rekor prior to version 1.1.1 may crash due to out of memory (OOM) conditions caused by reading archive metadata files into memory without checking their sizes first. Verification of a JAR file submitted to Rekor can cause an out of memory crash if files within the META-INF directory of the JAR are sufficiently large. Parsing of an APK file submitted to Rekor can cause an out of memory crash if the .SIGN or .PKGINFO files within the APK are sufficiently large. The OOM crash has been patched in Rekor version 1.1.1. There are no known workarounds.CVE-2023-33199chainguardaactl+223y ago26-05-2023 22:52

Rekor's goals are to provide an immutable tamper resistant ledger of metadata generated within a software projects supply chain. A malformed proposed entry of the `intoto/v0.0.2` type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal. This has been fixed in v1.2.0 of Rekor. Users are advised to upgrade. There are no known workarounds for this vulnerability.