CVE-2021-45261Public exploit

Process crash via uninitialized pointers in another_hunk

Published Dec 22, 2021 · Updated Aug 4, 2024

Invalid-pointer handling in GNU patch 2.7 allows context-dependent attackers to crash the utility with a malformed patch file. In src/pch.c, another_hunk leaves p_line entries uninitialized before cleanup passes their invalid values to free. Exploitation requires a user to invoke the command-line tool on attacker-controlled input; the observed consequence is a segmentation fault confined to that process.

CVSS severity5.5
Medium
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid-pointer handling in GNU patch 2.7 allows context-dependent attackers to crash the utility with a malformed patch file. In src/pch.c, another_hunk leaves p_line entries uninitialized before cleanup passes their invalid values to free. Exploitation requires a user to invoke the command-line tool on attacker-controlled input; the observed consequence is a segmentation fault confined to that process.

The record

CVE
CVE-2021-45261
Published
Dec 22, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-763, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.3SUSECVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-763Release of Invalid Pointer or Reference
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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