CVE-2021-29390Network attack vector

Crash or data disclosure via unsigned underflow

Published Aug 22, 2023 · Updated Oct 4, 2024

Heap buffer over-read in libjpeg-turbo 2.0.90 allows attackers to crash image-processing applications via a narrow progressive JPEG. In decompress_smooth_data in jdcoefct.c, an unsigned subtraction underflows when last_block_column is zero, passing the bounds test and reading a nonexistent second block column. The 2-byte read can expose adjacent heap data or crash the consuming process, and exploitation requires an application to decode the crafted image.

CVSS severity7.1
High
EPSS probability0.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer over-read in libjpeg-turbo 2.0.90 allows attackers to crash image-processing applications via a narrow progressive JPEG. In decompress_smooth_data in jdcoefct.c, an unsigned subtraction underflows when last_block_column is zero, passing the bounds test and reading a nonexistent second block column. The 2-byte read can expose adjacent heap data or crash the consuming process, and exploitation requires an application to decode the crafted image.

The record

CVE
CVE-2021-29390
Published
Aug 22, 2023
Updated
Oct 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

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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