CVE-2026-49478: sigstore fulcio · Server-Side Request Forgery (SSRF)
Affects sigstore fulcioSource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 1.8.6 soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-08-15.
- Patch
- Available – fixed in 1.8.6
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade sigstore fulcio to 1.8.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| sigstorefulcio | Affected
| Fixed in
|
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.
References
- github.com/sigstore/fulcio/security/advisories/GHSA-f5mr-q85p-6hh6 (opens in a new tab)
- github.com/sigstore/fulcio/pull/2354 (opens in a new tab)
- github.com/sigstore/fulcio/commit/378c654f48c3bafdced04ead7010aab2cb4c6ca1 (opens in a new tab)
- github.com/sigstore/fulcio/releases/tag/v1.8.6 (opens in a new tab)