CVE-2021-42715Public exploit

Application hang via zero-length HDR RLE runs

Published Oct 21, 2021 · Updated Aug 4, 2024

Infinite-loop denial of service in stb_image.h 1.33 through 2.27 allows attackers to hang applications via crafted HDR files. In stbi__hdr_load, end-of-file reads return zero, which the RLE scanline loop accepts as a zero-length run without advancing its index. The application must process the malformed image; the affected decoding thread never returns, causing an availability-only service interruption.

CVSS severity5.5
Medium
EPSS probability1.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite-loop denial of service in stb_image.h 1.33 through 2.27 allows attackers to hang applications via crafted HDR files. In stbi__hdr_load, end-of-file reads return zero, which the RLE scanline loop accepts as a zero-length run without advancing its index. The application must process the malformed image; the affected decoding thread never returns, causing an availability-only service interruption.

The record

CVE
CVE-2021-42715
Published
Oct 21, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-835, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 21, 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

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

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

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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