CVE-2021-33479Public exploit

Arbitrary code execution via pitch-array underflow

Published Nov 17, 2021 · Updated Nov 18, 2024

Stack buffer underflow in GOCR through 0.53-20200802 allows context-dependent attackers to execute arbitrary code via a crafted image. In pgm2asc.c, measure_pitch() reads four bytes before the stack-allocated pdists array while parsing the reproducer. The target must process attacker-supplied image data; the public reproducer demonstrates an AddressSanitizer-detected process abort.

CVSS severity7.8
High
EPSS probability1.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer underflow in GOCR through 0.53-20200802 allows context-dependent attackers to execute arbitrary code via a crafted image. In pgm2asc.c, measure_pitch() reads four bytes before the stack-allocated pdists array while parsing the reproducer. The target must process attacker-supplied image data; the public reproducer demonstrates an AddressSanitizer-detected process abort.

The record

CVE
CVE-2021-33479
Published
Nov 17, 2021
Updated
Nov 18, 2024
Vendor
GOCR Project
Product
GOCR
Classifications
CWE-787, CWE-119, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 18, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=gocr 0.53-20200802

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

GOCR Project · GOCRversion=gocr 0.53-20200802

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1203Exploitation for Client Execution

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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