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VulnerabilityPublished

CVE-2026-119284: joserfc · Compact JWS size guard allocates attacker-controlled segments before rejection

Affects joserfcSource GCVE Database

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Authoritative record:CVE-2026-119284· Medium 6.9

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

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.06.9
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Oct 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 30 Oct 2026.

What to do

Upgrade joserfc to 1.7.6.

Affected software

ProductAffectedFixed in
PyPIjoserfcAffected
  • <1.7.6
Fixed in
  • 1.7.6

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

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