5.5

CVE-2026-22703: Cosign verification accepts any valid Rekor entry under certain conditions

Analyzed
AliasesUBUNTU-CVE-2026-22703DEBIAN-CVE-2026-22703CGA-2522-fm22-gwm9
Published 10-01-2026Last modified 12-01-2026

Vulnerability summary

CVE-2026-22703 is a medium (CVSS 5.5) vulnerability in sigstore cosign. EPSS estimates a 0.11% chance of exploitation in the next 30 days, higher than 1.1% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.11%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 6 · Related 7
OPENSUSE-SU-2026:10232-1OPENSUSE-SU-2026:20386-1OPENSUSE-SU-2026:21483-1SUSE-SU-2026:0142-1SUSE-SU-2026:0777-1SUSE-SU-2026:20904-1

Timeline

  1. 10-01-2026
    PublishedVulnerability first disclosed.
  2. 12-01-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

8 scores · 8 sources · 1 version

EPSS trend

Probability

0.11%

Chance of exploitation in the next 30 days

Percentile

1%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.11% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Cosign

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard109 products
  • aactl< 0.4.12-r43
  • chainctl< 0.2.194-r0
  • cloudbeat-8.17All versions (No fix recorded)
  • cloudbeat-8.18All versions (No fix recorded)
  • cloudbeat-8.19< 8.19.16-r0
Wolfi22 products
  • aactl< 0.4.12-r43
  • falcoctl< 0.12.0-r0
  • flux-source-controller< 1.7.4-r5
  • gitsign< 0.14.0-r0
  • gitsign-credential-cache< 0.14.0-r0
Github.com/sigstore/cosign2 products
  • v2< 2.6.2
  • v3< 3.0.4
Alpine1 product
  • cosign≥ 3.0.0, < 2.6.3-r0
Debian1 product
  • cosignAll versions (No fix recorded) | < 2.6.2-1
Github.com/sigstore1 product
  • cosignAll versions (No fix recorded)
Sigstore1 product
  • cosign< 3.0.4 | < 2.6.2 | ≥ 3.0.0, < 3.0.4
Ubuntu1 product
  • cosignAll versions (No fix recorded)

8 vendors · 138 products

References

10 links