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CVE-2021-43313

HIGH
7.5
CVSS Score
Published: March 24, 2023 at 12:00 AM UTC
Updated: June 17, 2026 at 04:10 AM UTC
2 products affected across 2 vendorsUpxUpx

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Severity
HIGH7.5
Exploit prediction
EPSS 0.8%
SSVC
PoC

Description

A heap-based buffer overflow was discovered in upx, during the variable 'bucket' points to an inaccessible address. The issue is being triggered in the function PackLinuxElf32::invert_pt_dynamic at p_lx_elf.cpp:1688.

Affected

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

Upx· Upx
95%
v < 4.0.0
Affected range stops below 4.0.0, so it looks safe — our inference, not a vendor statement
Upx· Fedora Project
60%
v < 4.0.0-git-c6b9e3c62d15
Affected range stops below 4.0.0-git-c6b9e3c62d15, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

ExploitIssue TrackingPatch
Source: [email protected]
https://github.com/upx/upx/issues/378

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

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

CVSS

7.5HIGH[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-119CWE-787

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