CVE-2026-1837: A specially-crafted file can cause libjxl's decoder to write pixel data to uninitialized unallocated memory

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HIGH 7.5REMOTEUPGRADE

CVE-2026-1837 is a high-severity flaw (CVSS 7.5) affecting libjxl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A specially-crafted file can cause libjxl's decoder to write pixel data to uninitialized unallocated memory. Soon after that data from another uninitialized unallocated region is copied to pixel data. This can be done by requesting color transformation of grayscale images to another grayscale color space. Buffers allocated for 1-float-per-pixel are used as if they are allocated for 3-float-per-pixel. That happens only if LCMS2 is used as CMS eng

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 75%)
CISA exploited list	No
Weakness	CWE-805, CWE-770, CWE-787
Published	2026-02-11
Last modified	2026-07-15

Publisher (CNA): Google Inc. · Vendor: libjxl project

Last updated 2026-07-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-02-11 16:16 UTCPublished CVE record published
2026-07-15 02:18 UTCUpdated Record last modified

libjxl project libjxl UPGRADE

Affected: >= 0.9.0 and <= 0.11.1

Fixed in: newer than 0.11.1

Safe to downgrade to: a release before 0.9.0

1. Check installed version

apt-cache policy libjxl || rpm -q libjxl || libjxl --version

2. UPGRADE to newer than 0.11.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libjxl

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libjxl

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.9.0 (Debian / Ubuntu)

apt-cache madison libjxl sudo apt install libjxl=<VERSION_BEFORE_0.9.0> sudo apt-mark hold libjxl

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list libjxl sudo dnf downgrade libjxl-<VERSION_BEFORE_0.9.0> sudo dnf versionlock add libjxl

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-1837?

libjxl: upgrade to newer than 0.11.1. Exact commands for each OS are on this page.

Is CVE-2026-1837 being exploited?

CVE-2026-1837 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-1837 affect?

CVE-2026-1837 affects libjxl. Severity is high (CVSS 7.5). A specially-crafted file can cause libjxl's decoder to write pixel data to uninitialized unallocated memory. Soon after that data from another uninitialized unallocated region is copied to pixel data. This can be done by requesting color t

How urgent is CVE-2026-1837?

Priority 42/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-12474 MEDIUM 4.4 UPGRADE A specially-crafted file can cause libjxl's decoder to read pixel data from uninitialized (but allocated) memo
CVE-2024-11498 HIGH 7.5 UPGRADE There exists a stack buffer overflow in libjxl. A specifically-crafted file can cause the JPEG XL decoder to u
CVE-2024-11403 CRITICAL 9.8 UPGRADE There exists an out of bounds read/write in LibJXL versions prior to commit 9cc451b91b74ba470fd72bd48c121e9f33

References

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