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CVE-2023-23456

Upx: heap-buffer-overflow in packtmt::pack()

MEDIUM
5.5
CVSS Score
Published: January 12, 2023 at 12:00 AM UTC
Updated: June 17, 2026 at 05:37 AM UTC
2 products affected across 2 vendorsFedoraUpx

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Fedora· Fedora Projectrpm
95%
3637
Upx· Upx
95%
v < 2022-11-24
Affected range stops below 2022-11-24, so it looks safe — our inference, not a vendor statement

References (6)

Issue TrackingThird Party Advisory
Source: [email protected]
https://bugzilla.redhat.com/show_bug.cgi?id=2160381
PatchThird Party Advisory
Source: [email protected]
https://github.com/upx/upx/commit/510505a85cbe45e51fbd470f1aa8b02157c429d4
ExploitThird Party Advisory
Source: [email protected]
https://github.com/upx/upx/issues/632
Vendor Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EL3BVKIGG3SH6I3KPOYQAWCBD4UMPOPI/
Vendor Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TGEP3FBNRZXGLIA2B2ICMB32JVMPREFZ/
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2024/12/msg00013.html

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUM[email protected]
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-787

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