zipfile: bzip2/LZMA/Zstandard members decompress without a max_length bound, defeating chunked-read memory limits
Summary
| CVE | CVE-2026-15310 |
|---|---|
| State | PUBLISHED |
| Assigner | PSF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-25 15:16:30 UTC |
| Updated | 2026-09-17 01:16:43 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 2.1 LOW from [email protected]
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS: 0.003380000 probability, percentile 0.268900000 (date 2026-09-13)
Problem Types: CWE-400 | CWE-400 CWE-400
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 2.1 | LOW | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 2.1 | LOW | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
NoneUser Interaction
ActiveConfidentiality
NoneIntegrity
NoneAvailability
LowSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Python Software Foundation | CPython | affected 3.15.0rc2 python | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| mail.python.org/archives/list/[email protected]/thread/YUHXURX2WZG... | [email protected] | mail.python.org | |
| github.com/python/cpython/commit/f897dbf2f36a5935700b7c2d94d4681d2136b7d4 | [email protected] | github.com | |
| github.com/python/cpython/commit/e2311cfb3dd518f008f312fe0631f4f7490d237a | [email protected] | github.com | |
| github.com/python/cpython/commit/1b424c0178a01e155fd0267dc28a8fc1159b33a8 | [email protected] | github.com | |
| github.com/python/cpython/issues/156002 | [email protected] | github.com | |
| github.com/python/cpython/commit/31980e84b9a708424a0a1dfecde3fc991e313f89 | [email protected] | github.com | |
| github.com/python/cpython/commit/9d167992b59cf5e23c66b9ed742b13f5925f7d70 | [email protected] | github.com | |
| github.com/python/cpython/commit/f507e6946a3194e83e1d7b8ee6e14567175e46de | [email protected] | github.com | |
| github.com/python/cpython/pull/156003 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: tonghuaroot (童话) (https://github.com/tonghuaroot) (en)
CNA: Petr Viktorin (https://github.com/encukou) (en)
CNA: William Woodruff (https://github.com/woodruffw) (en)
There are currently no legacy QID mappings associated with this CVE.