When decompressing crafted zip files using the bzip/LZMA/Zstandard compressions, Python could use an
Source GCVE Database
Not known to be exploited · CVSS 2.1 Low · fixed in 3.15.0rc2 : update CPython when convenient.
Data as of 10 Nov 2026, 23:24 UTC
Thin evidence
One scorer or none| CNA (PSF) | CVSS 4.0 | 2.1 |
|---|
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.15.0rc2, 3.14.8, 3.13.16 +3
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 25 Aug 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 10 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
|
| Python Software FoundationCPython | Affected
| Fixed in
|
| Python Software FoundationCPython | Affected
| Fixed in
|
| Python Software FoundationCPython | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
When decompressing crafted zip files using the bzip/LZMA/Zstandard compressions, Python could use an attacker-controlled size to pre-allocate memory, possibly resulting in memory exhaustion.
References
- nvd.nist.gov/vuln/detail/CVE-2026-15310 (opens in a new tab)
- github.com/python/cpython/issues/156002 (opens in a new tab)
- github.com/python/cpython/pull/156003 (opens in a new tab)
- github.com/python/cpython/commit/09a2e7e6678b4f65449e7ad8f112c48f944591e2 (opens in a new tab)
- github.com/python/cpython/commit/1b424c0178a01e155fd0267dc28a8fc1159b33a8 (opens in a new tab)
- github.com/python/cpython/commit/31980e84b9a708424a0a1dfecde3fc991e313f89 (opens in a new tab)
- github.com/python/cpython/commit/6257029de42ef89b67f3d20137de87d43e197530 (opens in a new tab)
- github.com/python/cpython/commit/9d167992b59cf5e23c66b9ed742b13f5925f7d70 (opens in a new tab)
- github.com/python/cpython/commit/c2bfbcdd1a11690507a10bc0998f95b8dc6b6fac (opens in a new tab)
- github.com/python/cpython/commit/dcdd406ddbfc4cb29b24c3df17cbabe21d316ce1 (opens in a new tab)
- github.com/python/cpython/commit/e2311cfb3dd518f008f312fe0631f4f7490d237a (opens in a new tab)
- github.com/python/cpython/commit/f507e6946a3194e83e1d7b8ee6e14567175e46de (opens in a new tab)
- github.com/python/cpython/commit/f897dbf2f36a5935700b7c2d94d4681d2136b7d4 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)
- mail.python.org/archives/list/security-announce@python.org/thread/YUHXURX2WZGKGNA4ANYBQS2VZRYQ5JNK (opens in a new tab)