Vulnerability · CVE-2026-3644
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete.
Published Mar 16, 2026 · catalog updated Aug 13, 2026 · The fix for which
Check if you run it
No confirmed exploitation is on record for CVE-2026-3644. EPSS is 0.50%. Act only if a listed version of The fix for which is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (The fix for which).
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium6.0
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.50%
- Remediation
- Advisory link
- Affected products
- cpe python/python
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output().
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe python/python3.15.0
How to fix CVE-2026-3644
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-3644. EPSS is 0.50%. Act only if a listed version of The fix for which is installed.
Which versions are affected?
Compare what you have installed with 3.15.0. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-116; CWE-20: Improper Input Validation. EPSS 0.50%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Mar 16, 2026 · NIST NVD
Detected
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output().
Aug 13, 2026 · NIST NVD
Updated
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output().
Sources
- CVE.orgVulnerability recordCVE-2026-3644
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-3644
30-day exploitation probability 0.5%
first.org - NIST NVDVulnerability recordCVE-2026-3644
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the ou
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.