CVE-2023-23456: Upx: heap-buffer-overflow in packtmt::pack()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-01-12 · updated 2026-06-17
Weakness: CWE-787

Description

A heap-based buffer overflow issue was discovered in UPX in PackTmt::pack() in p_tmt.cpp file. The flow allows an attacker to cause a denial of service (abort) via a crafted file.

Affected products

Fedoraproject Fedora: 36, 37
upx: before 2022-11-24 — fixed in 2022-11-24

How to fix

Upgrade to a fixed version: upx 2022-11-24. Check the vendor advisory for mitigations.

References

https://bugzilla.redhat.com/show_bug.cgi?id=2160381
https://github.com/upx/upx/commit/510505a85cbe45e51fbd470f1aa8b02157c429d4
https://github.com/upx/upx/issues/632
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EL3BVKIGG3SH6I3KPOYQAWCBD4UMPOPI/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TGEP3FBNRZXGLIA2B2ICMB32JVMPREFZ/
https://bugzilla.redhat.com/show_bug.cgi?id=2160381
https://github.com/upx/upx/commit/510505a85cbe45e51fbd470f1aa8b02157c429d4
https://github.com/upx/upx/issues/632
https://lists.debian.org/debian-lts-announce/2024/12/msg00013.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EL3BVKIGG3SH6I3KPOYQAWCBD4UMPOPI/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TGEP3FBNRZXGLIA2B2ICMB32JVMPREFZ/

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