Red Hat Security Advisory: python3.12 security update
Affects Red Hat python3.12Source GCVE Database
Not known to be exploited · CVSS 8.7 High · fixed in Red Hat package updates : patch Red Hat CPython soon.
Data as of 1 Nov 2026, 01:56 UTC
- Patch
- Available – fixed in 3.15.0b4, 3.14.7, 3.13.15 +3
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Jul 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 31 Oct 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
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| 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
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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 python3.12 packages for Red Hat Enterprise Linux 8 that fix this vulnerability. Users should apply the security update as described in Red Hat advisory RHSA-2026:39893 and the referenced article https://access.redhat.com/articles/11258 to remediate the issue. No additional mitigation steps are indicated beyond applying the official patch.
Description
A denial of service vulnerability (CVE-2026-15308) exists in the Python 3.12 HTML parser due to repeated unterminated markup declarations. This flaw can cause excessive CPU consumption when parsing crafted HTML content. Red Hat has issued a security update for python3.12 in Red Hat Enterprise Linux 8 to address this issue.