CVE-2026-102272: Hermes agent · PyJWT BOM Bypass
Affects hermes-agentSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.4 High : upgrade to 0.22.4 soon.
Data as of 27 Oct 2026, 21:00 UTC
- Patch
- Available – fixed in 0.22.4
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 28 Sep 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 hermes-agent to 0.22.4.
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 has been committed to PyJWT that correctly handles UTF-8 BOM prefixes and uses JSON parsing to detect asymmetric keys, preventing this bypass. Users should upgrade to PyJWT version 0.22.4 or later where the fix is included. If you cannot patch yet, users should avoid configurations that accept both HS256 and RS256 algorithms simultaneously or implement additional validation to reject BOM-prefixed keys. No other mitigations are indicated by the vendor advisory.
Description
PyJWT version 2.13.0 contains a vulnerability where a UTF-8 BOM prefix in a JSON Web Key (JWK) bypasses a key validation guard, allowing an attacker to use an RSA public key as an HMAC secret. This enables forging JWT tokens with arbitrary claims when the verifier accepts both HS256 and RS256 algorithms. The vulnerability leads to complete authentication and authorization bypass. A fix has been committed but not yet released.
References
- github.com/jpadilla/pyjwt/security/advisories/GHSA-r6x4-923q-g947 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-102272 (opens in a new tab)
- github.com/jpadilla/pyjwt/commit/180783930de91876bc0d601f826a1f2956057291 (opens in a new tab)
- github.com/jpadilla/pyjwt (opens in a new tab)
- github.com/jpadilla/pyjwt/releases/tag/2.14.0 (opens in a new tab)