CVE-2021-35940

Memory disclosure or crash via unchecked month

Published Aug 23, 2021 · Updated Aug 4, 2024

Out-of-bounds read in Apache Portable Runtime 1.7.0 allows local users to disclose memory or crash a linked process via an invalid month. The apr_time_exp_get code indexes a 12-entry dayoffset array without first validating tm_mon; Win32 paths likewise fail to validate wMonth or tm_mon. Reachability requires a linked application to pass an attacker-controlled exploded-time month, bounding the impact to that application process.

CVSS severity7.1
High
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Apache Portable Runtime 1.7.0 allows local users to disclose memory or crash a linked process via an invalid month. The apr_time_exp_get code indexes a 12-entry dayoffset array without first validating tm_mon; Win32 paths likewise fail to validate wMonth or tm_mon. Reachability requires a linked application to pass an attacker-controlled exploded-time month, bounding the impact to that application process.

The record

CVE
CVE-2021-35940
Published
Aug 23, 2021
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Portable Runtime (APR)
Classifications
CWE-125
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 23, 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?

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  1. Affected versionversion=Apache Portable Runtime 1.7.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Portable Runtime (APR)version=Apache Portable Runtime 1.7.0

Published CVSS scores

7.1NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read

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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