CVE-2026-6100

Aliases:RHSA-2026:52400UBUNTU-CVE-2026-6100DEBIAN-CVE-2026-6100ALPINE-CVE-2026-6100CGA-5m77-63wh-vhhhCGA-8rj5-pwmw-2wm5CGA-96fx-93m7-m2ppCGA-cmr8-cc58-qjg7CGA-gw5v-fvh4-9pxrCGA-hq26-pcqg-hvvpCGA-m7qp-99cp-h7qjCGA-mqvf-66wx-9p3pCGA-4h5f-p9cx-c824CGA-4hgr-79qh-c53pCGA-r845-9w2j-fj7qCGA-w599-3365-3555
Advisory lineage Upstream: 0 Downstream: 50
Awaiting Analysis
Published: 13 Apr 2026, 17:15
Last modified:13 Aug 2026, 00:27

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.1 CRITICAL
v4.0 (cve.org)
EPSS Score
0.58% LOW
1% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

13 Apr 2026, 17:15
Published
Vulnerability first disclosed
13 Aug 2026, 00:27
Last Modified
Vulnerability information updated

Description

Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re-used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition. The vulnerability is only present if the program re-uses decompressor instances across multiple decompression calls even after a `MemoryError` is raised during decompression. Using the helper functions to one-shot decompress data such as `lzma.decompress()`, `bz2.decompress()`, `gzip.decompress()`, and `zlib.decompress()` are not affected as a new decompressor instance is used per call. If the decompressor instance is not re-used after an error condition, this usage is similarly not vulnerable.

CVSS Metrics

  • v4.0•CRITICAL•Score: 9.1CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
  • v4.0•CRITICAL•Score: 9.1CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/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
  • v3.1•HIGH•Score: 8.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.58%• Percentile: 46%

Techniques & Countermeasures

  • CWE-416•Use After Free

    The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

  • CWE-787•Out-of-bounds Write

    The product writes data past the end, or before the beginning, of the intended buffer.

  • CWE-825•Expired Pointer Dereference

    The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.

Affected Systems

  • alpine•python3

    < 3.12.14-r0 | < 3.12.14-r0 | < 3.12.14-r0

  • chainguard•python-3.10

    < 3.10.20-r3

  • chainguard•python-3.11

    < 3.11.15-r2

  • chainguard•python-3.12

    < 3.12.13-r3

  • chainguard•python-3.13

    < 3.13.13-r2

  • chainguard•python-3.14

    < 3.14.4-r3

  • chainguard•python-3.9

    all

  • wolfi•python-3.10

    < 3.10.20-r3

  • wolfi•python-3.11

    < 3.11.15-r2

  • wolfi•python-3.12

    < 3.12.13-r3

  • wolfi•python-3.13

    < 3.13.13-r2

  • wolfi•python-3.14

    < 3.14.4-r3

  • debian•python2.7

    all

  • debian•python3.11

    < 3.11.2-6+deb12u8

  • debian•python3.13

    < 3.13.5-2+deb13u2 | < 3.13.14-1

  • debian•python3.14

    < 3.14.5~rc1-1

  • debian•python3.9

    < 3.9.2-1+deb11u6

  • ubuntu•pypy3

    all | all | all | all | all

  • ubuntu•python2.7

    all

  • ubuntu•python3.10

    < 3.10.12-1~22.04.16

  • ubuntu•python3.11

    all | all

  • ubuntu•python3.12

    < 3.12.3-1ubuntu0.15

  • ubuntu•python3.13

    all

  • ubuntu•python3.14

    all | < 3.14.4-1ubuntu0.1

  • ubuntu•python3.4

    all

  • ubuntu•python3.5

    all

  • ubuntu•python3.6

    all

  • ubuntu•python3.7

    all

  • ubuntu•python3.8

    all

  • ubuntu•python3.9

    all

  • python software foundation•cpython

    < 3.15.0 | < 3.13.14 | < 3.10.21 | ≥ 3.11.0, < 3.11.16 | ≥ 3.12.0, < 3.12.14 | ≥ 3.13.0, < 3.13.14 | ≥ 3.14.0a1, < 3.14.5rc1 | ≥ 3.15.0a1, < 3.15.0b1

  • redhat•python3

    < 0:3.6.8-21.el7_9.7

  • redhat•python3-debug

    < 0:3.6.8-21.el7_9.7

  • redhat•python3-debuginfo

    < 0:3.6.8-21.el7_9.7

  • redhat•python3-devel

    < 0:3.6.8-21.el7_9.7

  • redhat•python3-idle

    < 0:3.6.8-21.el7_9.7

  • redhat•python3-libs

    < 0:3.6.8-21.el7_9.7

  • redhat•python3-test

    < 0:3.6.8-21.el7_9.7

  • redhat•python3-tkinter

    < 0:3.6.8-21.el7_9.7

References (65)