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NVD / CVE Program· CNA PSF

CVE-2025-8291: ZIP64 End of Central Directory (EOCD) Locator record offset not checked

Noroxi assessment

Priority: Monitor (action score 17/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.46% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: Python Software Foundation CPython 3.10.19, 3.11.14, 3.12.12; azl3 python3 3.12.9-4 on Azure Linux 3.0 3.12.9-5; azl3 python3 3.12.9-5 on Azure Linux 3.0 3.12.9-5.

Low priority for now. Upgrade to Python Software Foundation CPython 3.10.19, 3.11.14, 3.12.12; azl3 python3 3.12.9-4 on Azure Linux 3.0 3.12.9-5; azl3 python3 3.12.9-5 on Azure Linux 3.0 3.12.9-5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The 'zipfile' module would not check the validity of the ZIP64 End of Central Directory (EOCD) Locator record offset value would not be used to locate the ZIP64 EOCD record, instead the ZIP64 EOCD record would be assumed to be the previous record in the ZIP archive. This could be abused to create ZIP archives that are handled differently by the 'zipfile' module compared to other ZIP implementations. Remediation maintains this behavior, but checks that the offset specified in the ZIP64 EOCD Locator record matches the expected value.

MediumCVSS 4.3 · v3.1—No exploit Fix available
Published
Oct 7, 2025
Updated
Oct 8, 2026
EPSS
0.4% · 40th percentile

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · PSF
4.3
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (PSF). Independent of NVD's CPE analysis and usually ahead of it.

  • Python Software Foundation CPython

    • before 3.9.24affected · python
    • 3.10.0 and later · before 3.10.19affected · python
    • 3.11.0 and later · before 3.11.14affected · python
    • 3.12.0 and later · before 3.12.12affected · python
    • 3.13.0 and later · before 3.13.10affected · python
    • 3.14.0 and later · before 3.14.1affected · python

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10python-unversioned-commandbefore 3.12.12-1.el10_13.12.12-1.el10_1
AlmaLinux:8python3.12before 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python3.12-debugbefore 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python3.12-develbefore 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python3.12-idlebefore 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python3.12-libsbefore 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python3.12-rpm-macrosbefore 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python3.12-testbefore 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python3.12-tkinterbefore 3.12.12-1.el8_103.12.12-1.el8_10
AlmaLinux:8python39before 3.9.25-2.module_el8.10.0+4083+53cad1fb3.9.25-2.module_el8.10.0+4083+53cad1fb
AlmaLinux:8python39-attrsbefore 20.3.0-2.module_el8.6.0+2780+a40f65e120.3.0-2.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-cffibefore 1.14.3-2.module_el8.6.0+2780+a40f65e11.14.3-2.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-cffibefore 1.14.3-2.module_el8.6.0+3248+c431e88c1.14.3-2.module_el8.6.0+3248+c431e88c
AlmaLinux:8python39-chardetbefore 3.0.4-19.module_el8.6.0+2780+a40f65e13.0.4-19.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-cryptographybefore 3.3.1-3.module_el8.10.0+3765+2f9a457d3.3.1-3.module_el8.10.0+3765+2f9a457d
AlmaLinux:8python39-Cythonbefore 0.29.21-5.module_el8.6.0+3248+c431e88c0.29.21-5.module_el8.6.0+3248+c431e88c
AlmaLinux:8python39-Cythonbefore 0.29.21-5.module_el8.6.0+2780+a40f65e10.29.21-5.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-debugbefore 3.9.25-2.module_el8.10.0+4083+53cad1fb3.9.25-2.module_el8.10.0+4083+53cad1fb
AlmaLinux:8python39-develbefore 3.9.25-2.module_el8.10.0+4083+53cad1fb3.9.25-2.module_el8.10.0+4083+53cad1fb
AlmaLinux:8python39-idlebefore 3.9.25-2.module_el8.10.0+4083+53cad1fb3.9.25-2.module_el8.10.0+4083+53cad1fb
AlmaLinux:8python39-idnabefore 2.10-4.module_el8.10.0+3849+a48d89aa2.10-4.module_el8.10.0+3849+a48d89aa
AlmaLinux:8python39-iniconfigbefore 1.1.1-2.module_el8.6.0+2780+a40f65e11.1.1-2.module_el8.6.0+2780+a40f65e1
AlmaLinux:8python39-libsbefore 3.9.25-2.module_el8.10.0+4083+53cad1fb3.9.25-2.module_el8.10.0+4083+53cad1fb
AlmaLinux:8python39-lxmlbefore 4.6.5-1.module_el8.6.0+3248+c431e88c4.6.5-1.module_el8.6.0+3248+c431e88c

+96

Same product

python software foundation: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-115557Distrust compromised intermediate certificates in ssl module
    37Monitor
  • CVE-2025-4517Arbitrary writes via tarfile realpath overflow
    37Monitor
  • CVE-2026-19445Use-after-free of a server-side SSLContext when sni_callback switches contexts
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-6069Jun 17, 2025 · HTMLParser quadratic complexity when processing malformed inputs
    17Monitor
  • ← EarlierCVE-2025-8194Jul 28, 2025 · Tarfile infinite loop during parsing with negative member offset
    30Monitor
  • Later →CVE-2025-11468Jan 20, 2026 · Folding email comments of unfoldable characters doesn't preserve parenthesis
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Python Software Foundation CPython3.10.19Vendor (CNA)
Python Software Foundation CPython3.11.14Vendor (CNA)
Python Software Foundation CPython3.12.12Vendor (CNA)
Python Software Foundation CPython3.13.10Vendor (CNA)
Python Software Foundation CPython3.14.1Vendor (CNA)
Python Software Foundation CPython3.9.24Vendor (CNA)
azl3 python3 3.12.9-4 on Azure Linux 3.03.12.9-5 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 python3 3.12.9-5 on Azure Linux 3.03.12.9-5 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 python3 3.9.19-15 on CBL Mariner 2.03.9.19-16 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 python3 3.9.19-16 on CBL Mariner 2.03.9.19-16 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:python-unversioned-command3.9.25-2.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python33.9.25-2.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3-debug3.9.25-2.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3-devel3.9.25-2.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3-idle3.9.25-2.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3.123.12.12-1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3.12-debug3.12.12-1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3.12-devel3.12.12-1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3.12-idle3.12.12-1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3.12-libs3.12.12-1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3.12-test3.12.12-1.el9_7 · AlmaLinux:9Package registry (OSV)
almalinux:python3.12-tkinter3.12.12-1.el9_7 · AlmaLinux:9Package registry (OSV)
debian:pypy37.3.21+dfsg-1 · Debian:14Package registry (OSV)
debian:python3.113.11.2-6+deb12u7 · Debian:12Package registry (OSV)
debian:python3.133.13.5-2+deb13u1 · Debian:13Package registry (OSV)
debian:python3.143.14.0-3 · Debian:14Package registry (OSV)
debian:python3.93.9.2-1+deb11u4 · Debian:11Package registry (OSV)
opensuse:python2.7.18-150000.86.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:python-base2.7.18-150000.86.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:python-doc2.7.18-150000.86.1 · openSUSE:Leap 15.6Package registry (OSV)

+47

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-1285 · Improper Validation of Specified Index, Position, or Offset in Input

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (11 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records