CVE-2026-119284: joserfc · Compact JWS size guard allocates attacker-controlled segments before rejection
Affects joserfcSource GCVE Database
Not known to be exploited · CVSS 6.9 Medium : upgrade to 1.7.6 when convenient.
Data as of 30 Oct 2026, 18:05 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 4.0 | 6.9 |
|---|
- Patch
- Available – fixed in 1.7.6
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 29 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 joserfc to 1.7.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PyPIjoserfc | 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 patch is available in joserfc version 1.7.6 that addresses this issue by validating the total input size before splitting the bytes, preventing large attacker-controlled allocations. Users should upgrade to version 1.7.6 or later to mitigate this vulnerability. No additional mitigation steps are required beyond applying the official fix.
Description
joserfc versions prior to 1.7.6 have a vulnerability in their compact JWS size guard. The library allocates attacker-controlled segments by splitting the input bytes before validating their size, causing an additional large memory allocation before rejecting oversized inputs. This can lead to increased memory usage and potential denial of service due to memory exhaustion. A fix is available in version 1.7.6 that adds size checks before splitting the input.
References
- github.com/authlib/joserfc/security/advisories/GHSA-9pg5-8c7x-5hfx (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-119284 (opens in a new tab)
- github.com/authlib/joserfc/commit/397e04f4bbce0b94d86e31c1c003f4640af8fb39 (opens in a new tab)
- github.com/authlib/joserfc (opens in a new tab)
- github.com/authlib/joserfc/releases/tag/1.7.6 (opens in a new tab)