hermes-agent · OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client
Affects hermes-agentSource GCVE Database
Not known to be exploited · CVSS 8.4 High : upgrade to 2026.9.21_2 soon.
Data as of 31 Oct 2026, 17:07 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 4.0 | 8.4 |
|---|
- Patch
- Available – fixed in 2026.9.21_2
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 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 30 Oct 2026.
What to do
Upgrade hermes-agent to 2026.9.21_2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewhermes-agentpkg:brew/hermes-agentOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in OAuthlib version 2026.9.21_2. Users should upgrade to this version or later to resolve the vulnerability. Until patched, deployments should verify that their RequestValidator implementations do not authorize based solely on the client_id argument passed by OAuthlib and instead rely on the authenticated client object (request.client) to prevent this attack. No other mitigations are specified.
Description
OAuthlib contains a vulnerability in its token grant handlers where an authenticated low-privilege client can supply a different client_id in the token request body, causing grant and scope validation to be performed under that other client identity. This affects the client_credentials and password grant flows. The flaw allows a low-privilege client to obtain tokens with scopes or grant types intended for a higher-privilege client if the application validator authorizes based on the attacker-supplied client_id argument. The issue is fixed in version 2026.9.21_2.
References
- github.com/oauthlib/oauthlib/security/advisories/GHSA-7984-qgvg-3j9c (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-118669 (opens in a new tab)
- github.com/oauthlib/oauthlib/pull/920 (opens in a new tab)
- github.com/oauthlib/oauthlib/commit/c951a1d09f99f14e3240973fa83c4f4287d4753d (opens in a new tab)
- github.com/oauthlib/oauthlib (opens in a new tab)
- github.com/oauthlib/oauthlib/releases/tag/v4.0.0 (opens in a new tab)