CVE-2026-15308
Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7, and 1 more
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- Python Software Foundation CPython
fixed in 3.10.21; From 3.11.0 · fixed in 3.11.16; From 3.12.0 · fixed in 3.12.14; From 3.13.0 · fixed in 3.13.15; From 3.14.0 · fixed in 3.14.7; From 3.15.0a1 · fixed in 3.15.0b4