CVE-2025-71263

Local root escalation via unbounded password input

Published Mar 13, 2026 · Updated Mar 13, 2026

Classic buffer overflow in AT&T Bell Labs UNIX 4 su allows local users to gain root privileges through an overlong password. The su.c input loop writes getchar() bytes into the fixed 100-byte password array until newline or NUL without tracking its length. The setuid-root command is locally reachable without the root password; adjacent-memory corruption grants a root shell, although the published demonstration confirms only a crash.

CVSS severity7.4
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Classic buffer overflow in AT&T Bell Labs UNIX 4 su allows local users to gain root privileges through an overlong password. The su.c input loop writes getchar() bytes into the fixed 100-byte password array until newline or NUL without tracking its length. The setuid-root command is locally reachable without the root password; adjacent-memory corruption grants a root shell, although the published demonstration confirms only a crash.

The record

CVE
CVE-2025-71263
Published
Mar 13, 2026
Updated
Mar 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1068
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 13, 2026Record 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

7.4MITRECVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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