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NVD / CVE Program· CNA VulnCheck

CVE-2026-66038: FFmpeg LCL/ZLIB Video Decoder Information Disclosure via lcldec.c

Noroxi assessment

Priority: Monitor (action score 28/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.24% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: ffmpeg (Debian:14) 7:9.0.2-1; ffmpeg-4 (openSUSE:Leap 16.0) 4.4.7-bp160.3.1; ffmpeg-7 (openSUSE:Leap 16.0) 7.1.4-160000.3.1.

Low priority for now. Upgrade to ffmpeg (Debian:14) 7:9.0.2-1; ffmpeg-4 (openSUSE:Leap 16.0) 4.4.7-bp160.3.1; ffmpeg-7 (openSUSE:Leap 16.0) 7.1.4-160000.3.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

FFmpeg through 8.1.2, fixed in commit 8670835, contains an information disclosure vulnerability in the LCL/ZLIB video decoder that allows attackers to expose uninitialized heap memory by supplying a valid zlib stream that inflates to fewer bytes than the expected frame size. The zlib_decomp() function in lcldec.c treats short decompression as non-fatal and continues to the RGB24 conversion path, which copies a full frame's worth of rows from the allocation buffer using original frame dimensions, causing uninitialized heap contents including pointer-derived allocator bytes to be copied into the attacker-observable AVFrame output and potentially defeating ASLR in long-lived media processing services.

HighCVSS 7.1 · v4.0—No exploit Fix available
Published
Jul 24, 2026
Updated
Aug 6, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
7.1
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-66038

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ffmpegffmpeg

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • ffmpeg ffmpegup to 8.1.2 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

  • FFmpeg FFmpeg

    • 86708357d126af84c16f80d9c57335d1e8c845c5not affected
    • up to and including 8.1.2affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12ffmpegfrom 0—
Debian:14ffmpegbefore 7:9.0.2-17:9.0.2-1
openSUSE:Leap 16.0ffmpeg-4before 4.4.7-bp160.3.14.4.7-bp160.3.1
openSUSE:Leap 16.0ffmpeg-7before 7.1.4-160000.3.17.1.4-160000.3.1
openSUSE:Tumbleweedffmpeg-4before 4.4.8-3.14.4.8-3.1
openSUSE:Tumbleweedffmpeg-7before 7.1.5-2.17.1.5-2.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSffmpeg-4before 4.4.8-150400.3.72.14.4.8-150400.3.72.1
SUSE:Linux Enterprise Module for Package Hub 15 SP7ffmpeg-4before 4.4.8-150600.13.52.14.4.8-150600.13.52.1
SUSE:Linux Enterprise Server 16.0ffmpeg-7before 7.1.4-160000.3.17.1.4-160000.3.1

Same product

ffmpeg: all records

Other highest-scoring records for the same primary product.

  • CVE-2009-4637FFmpeg 0.5 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via unknown vectors that trigger
    45Plan
  • CVE-2016-10190Heap-based buffer overflow in libavformat/http.c in FFmpeg before 2.8.10, 3.0.x before 3.0.5, 3.1.x before 3.1.6, and 3.2.x before 3.2.2 all
    42Plan
  • CVE-2009-4634Multiple integer underflows in FFmpeg 0.5 allow remote attackers to cause a denial of service and possibly execute arbitrary code via a craf
    42Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-66036Jul 24, 2026 · FFmpeg Heap Out-of-Bounds Write in vf_hqdn3d Filter
    30Monitor
  • ← EarlierCVE-2026-66037Jul 24, 2026 · FFmpeg IAMF Demuxer Uncontrolled Resource Consumption via mix_presentation_obu()
    28Monitor
  • Later →CVE-2026-66039Jul 24, 2026 · FFmpeg MACE6 Audio Decoder Heap Out-of-Bounds Write via CAF File
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:ffmpeg7:9.0.2-1 · Debian:14Package registry (OSV)
opensuse:ffmpeg-44.4.8-3.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:ffmpeg-77.1.5-2.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:ffmpeg-44.4.8-150400.3.72.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:ffmpeg-77.1.4-160000.3.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-7062913 days apartFFmpeg 3.0 < 9.0 Uninitialized Heap Memory Read in RSCC Decoder
    27Monitor
  • CVE-2026-7063013 days apartFFmpeg 3.0 < 9.0 Uninitialized Heap Memory Read in Screenpresso Decoder
    27Monitor
  • CVE-2026-7063113 days apartFFmpeg 0.5 < 9.0 Uninitialized Heap Memory Read in TIFF Decoder
    27Monitor
  • CVE-2026-10767676 days apartFFmpeg through 9.0.2 Uninitialized Memory Disclosure via HDR10+ Metadata Serializer
    19Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
P
Scope
X

Weakness class (CWE)

CWE-908 · Use of Uninitialized Resource

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records