8.7

CVE-2026-49478: sigstore fulcio Server-Side Request Forgery (SSRF)

CVSS: 8.7v3.1HighDeferred
AliasesUBUNTU-CVE-2026-49478DEBIAN-CVE-2026-49478CGA-24rw-wpj3-g8jx
Published 13-08-2026Last modified 15-08-2026
Open JSON

Vulnerability summary

CVE-2026-49478 is a high (CVSS 8.7) Server-Side Request Forgery (SSRF) vulnerability in sigstore fulcio. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.4% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v3.1 (CVE.org)
EPSS score
0.28%
0%100%
Low · +0.11 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 2
OPENSUSE-SU-2026:21483-1CGA-M9FM-V3RR-527Q

Timeline

  1. 13-08-2026
    PublishedVulnerability first disclosed.
  2. 15-08-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.28%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

+0.11 pp

From 0.18% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.28%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard125 products
  • aactl< 0.4.12-r58
  • buildah< 1.44.0-r8
  • buildah-fips< 1.44.0-r5
  • chainctl< 0.2.300-r1
  • chainctl-fips< 0.2.300-r1
Wolfi38 products
  • aactl< 0.4.12-r58
  • buildah< 1.44.0-r8
  • falco-no-driver< 0.45.0-r0
  • falcoctl< 0.13.0-r9
  • flux-source-controller< 1.9.1-r1
Debian1 product
  • golang-github-sigstore-fulcioAll versions (No fix recorded) | < 1.8.7-1
Github.com/sigstore1 product
  • fulcio< 1.8.6
Sigstore1 product
Ubuntu1 product
  • golang-github-sigstore-fulcioAll versions (No fix recorded)

6 vendors · 167 products

References

10 links