Red Hat Security Advisory: python3.9 security update
Affects Red Hat python3.9Source GCVE Database
Not known to be exploited · CVSS 5.9 Medium · fixed in Red Hat package updates : update Red Hat cpython when convenient.
Data as of 5 Nov 2026, 18:05 UTC
- Patch
- Available – fixed in 3.15.0a6, 3.14.3, 3.13.12 +3
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 20 Jan 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 5 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Python Software FoundationCPython | Affected
| Fixed in
|
| Python Software FoundationCPython | Affected
| Fixed in
|
| Python Software FoundationCPython | Affected
| Fixed in
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| Python Software FoundationCPython | Affected
| Fixed in
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| Python Software FoundationCPython | Affected
| Fixed in
|
| Python Software FoundationCPython | Affected
| Fixed in
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Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Red Hat has released updated python3.9 packages for Red Hat Enterprise Linux 9 that fix this vulnerability. Users should apply the official Red Hat security update RHSA-2026:18693 to remediate this issue. For detailed update instructions, refer to Red Hat's article at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated by the vendor.
Description
A security update for python3.9 in Red Hat Enterprise Linux 9 addresses a vulnerability in the cpython wsgiref.headers.Headers module that allows header newline injection (CVE-2026-0865). This issue could potentially allow injection of newline characters into HTTP headers, which may lead to security risks. Red Hat has rated this update as having a moderate security impact and has released updated packages to fix the issue.
References
- access.redhat.com/errata/RHSA-2026:18693 (opens in a new tab)
- docs.redhat.com/en/documentation/red_hat_enterprise_linux/9/html/9.8_release_notes/index (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2431367 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_18693.json (opens in a new tab)