CVE-2026-20911Public exploitNetwork attack vector

Memory corruption via unvalidated Huffman code counts

Published Apr 7, 2026 · Updated Apr 7, 2026

A heap-based buffer overflow in LibRaw commits 0b56545 and d20315b allows attackers to corrupt memory via a crafted RAW image file. HuffTable::initval copies file-derived Huffman-code counts into bits, sizes hufftable only as 2^nbits, then writes entries without validating that their weighted total fits the allocation. Processing the malicious file triggers an out-of-bounds heap write, causing a crash and corrupting memory within the consuming application's process.

CVSS severity9.8
Critical
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A heap-based buffer overflow in LibRaw commits 0b56545 and d20315b allows attackers to corrupt memory via a crafted RAW image file. HuffTable::initval copies file-derived Huffman-code counts into bits, sizes hufftable only as 2^nbits, then writes entries without validating that their weighted total fits the allocation. Processing the malicious file triggers an out-of-bounds heap write, causing a crash and corrupting memory within the consuming application's process.

The record

CVE
CVE-2026-20911
Published
Apr 7, 2026
Updated
Apr 7, 2026
Vendor
LibRaw LLC
Product
LibRaw
Classifications
CWE-131, CWE-120, CAPEC-100, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 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?

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

  1. Affected versionversion=Commit 0b56545
  2. Affected versionversion=Commit d20315b

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LibRaw LLC · LibRawversion=Commit 0b56545; version=Commit d20315b

Published CVSS scores

9.8Cisco TalosCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5Red Hat Security Data PlatformCVSS:3.1/AV:N/AC:H/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

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 exploitPublished

Weakness, pattern, technique

CWE-131Incorrect Calculation of Buffer Size
CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CAPEC-100Overflow Buffers
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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