CVE-2026-81868: SteeltoeOSS security-advisories · Authentication Bypass Using an Alternate Path or Channel
Affects SteeltoeOSS security-advisoriesSource CVE Database V5
Not known to be exploited · CVSS 6.5 Medium : upgrade to 4.3.0 when convenient.
Data as of 1 Nov 2026, 11:03 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.3.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 1 Nov 2026.
What to do
Upgrade security-advisories and steeltoeoss/Steeltoe to 4.3.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| SteeltoeOSSsecurity-advisories | Affected
| Fixed in
|
GitHubsteeltoeoss/Steeltoepkg:github/steeltoeoss/SteeltoeOther threats | Affected
| Fixed in
|
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AI-suggested
Upgrade Steeltoe.Security.Authorization.Certificate to version 4.3.0 or later, where this authentication bypass vulnerability is fixed. Until upgrading, restrict inbound requests to trusted proxy source IPs to prevent attackers from spoofing the X-Client-Cert header. No other vendor advisories indicate alternative mitigations or that the issue is already mitigated.
Description
Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. Prior to 4.3.0, Steeltoe.Security.Authorization.Certificate deployments using AddOrgAndSpacePolicies() and UseCertificateAuthorization() trust the public certificate supplied in the X-Client-Cert request header without proving possession of the corresponding private key. Common Cloud Foundry routers do not remove this header from inbound requests. When inbound requests are not restricted to a known trusted proxy source IP, an attacker who obtains the public certificate of an application instance in the target organization or space and can reach the application can spoof X-Client-Cert to bypass the SameOrg and SameSpace policies for the certificate validity period. This issue is fixed in version 4.3.0.