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VulnerabilityPublished

CVE-2026-16052: attribute values · http.cookies.Morsel class allows separator semicolons

Source GCVE Database

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Authoritative record:CVE-2026-16052· Low 2.3

Not known to be exploited · CVSS 2.3 Low : upgrade to 3.16.0 when convenient.

Data as of 12 Nov 2026, 19:19 UTC

CVSS 4.0 base score
2.3Low
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (PSF)CVSS 4.02.3
Patch
Available – fixed in 3.16.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Nov 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 12 Nov 2026.

What to do

Upgrade CPython to 3.16.0.

Affected software

ProductAffectedFixed in
Python Software FoundationCPythonAffected
  • <3.16.0
Fixed in
  • 3.16.0
GitHubCPythonpkg:github/CPythonOther threatsAffected
  • <3.16.0
Fixed in
  • 3.16.0

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

Description

The http.cookies.Morsel class allows separator semicolons in attribute values and includes them verbatim in all output formats. An attacker who can control these values could use this to relax the cookie's Domain or SameSite restrictions.

References

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