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CVE-2026-48522VulnerabilityPublished Updated

hermes-agent · PyJWKClient: missing scheme allowlist enables CVE-2024-21643-class SSRF + token forgery via file://, ftp://, data

Affects hermes-agentSource GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-48522· Medium 4.2

Not known to be exploited · CVSS 4.2 Medium : upgrade to 2026.7.1 when convenient.

Data as of 30 Oct 2026, 09:02 UTC

CVSS 3.1 base score
4.2Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 2026.7.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 29 Oct 2026.

What to do

Upgrade hermes-agent to 2026.7.1.

Affected software

ProductAffectedFixed in
Homebrewhermes-agentpkg:brew/hermes-agentOther threatsAffected
  • >=2026.4.30 <2026.7.1
Fixed in
  • 2026.7.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available in PyJWT version 2026.7.1 that adds an allowed_schemes parameter to PyJWKClient to restrict URL schemes to http and https. Applications should upgrade to this fixed version. Until patched, applications should validate and restrict the jku URL scheme to prevent non-http(s) schemes from being used. The vendor advisory recommends pre-validating the URL scheme before fetching to prevent SSRF and token forgery.

Description

PyJWKClient in PyJWT versions before 2026.7.1 does not restrict URL schemes when fetching JSON Web Key Sets (JWKS), allowing attacker-controlled URLs with schemes like file://, ftp://, or data:. This can lead to server-side request forgery (SSRF) to local files or other resources. Additionally, if an attacker can write to a location referenced by a file:// URL, they can forge JWT tokens that the application will accept as valid. The vulnerability is fixed in version 2026.7.1 by adding an allowed schemes whitelist.

References

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