CVE-2026-66038

MEDIUMNVD 6.56.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-24. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-48740 (ENISA EUVD) · GHSA-8mx4-8xfc-qr43 (GitHub Security Advisories)Source: ENISA EUVD

6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
15th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 24, 2026

Last Modified

August 7, 2026

Advisory Details (3)

Auto-updated Jul 25, 2026
Patch available.
Web page

FFmpeg LCL/ZLIB Video Decoder Information Disclosure via lcldec.c | Advisories | VulnCheck

https://www.vulncheck.com/advisories/ffmpeg-lcl-zlib-video-decoder-information-disclosure-via-lcldec-c
Web page

#23626 - avcodec/lcldec: zero the not-decoded tail to avoid heap disclosure - FFmpeg/FFmpeg - FFmpeg Forgejo

https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23626
Web page

avcodec/lcldec: zero the not-decoded tail to avoid heap disclosure · e7cbfd1c50 - FFmpeg/FFmpeg - FFmpeg Forgejo

https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/e7cbfd1c507b57a806a5825b87d609963e862c8c

Vendor Advisories for CVE-2026-66038(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibswscale9 (7:8.0.1-3ubuntu2+esm3) @ resolute2026-10-22ubuntu
ubuntulibswscale-ffmpeg3 (7:2.8.17-0ubuntu0.1+esm15) @ xenial2026-10-22ubuntu
redhatrhoai/odh-vllm-gaudi-rhel9:17891212632026-09-30redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
ffmpeg7:4.3.2-0+deb11u2 ... 7:8.1.2-2 (91 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ffmpeg7:5.1.3-1 ... 7:9.0.2-1 (60 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
ffmpeg7:7.1.1-1 ... 7:9.0.2-1 (24 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ffmpeg7:7.1.1-1 ... 7:9.0.1-1 (19 versions)
  • every version up to 7:9.0.2-1: fixed in 7:9.0.2-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 43× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 231 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 131 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  2. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  3. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  4. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  5. 2026-10-30 07:55 UTCOSV refresh
  6. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  7. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  8. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  9. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  10. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  11. 2026-10-25 14:11 UTCEG score recompute
  12. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  13. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  14. 2026-10-22 19:37 UTCEG score recompute
  15. 2026-10-22 19:37 UTCVendor advisory
  16. 2026-10-22 19:37 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  17. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  18. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  19. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  20. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  21. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  22. 2026-10-18 03:21 UTCEG score recompute
  23. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  24. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  25. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
Show 75 more
  1. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  2. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  3. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  4. 2026-10-12 15:46 UTCEG score recompute
  5. 2026-10-11 19:31 UTCEG score recompute
  6. 2026-10-11 16:46 UTCEG score recompute
  7. 2026-10-11 14:07 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  11. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  13. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  14. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  16. 2026-10-04 07:42 UTCEG score recompute
  17. 2026-10-04 07:42 UTCVendor advisory
  18. 2026-10-04 07:42 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  19. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  20. 2026-10-02 19:53 UTCEG score recompute
  21. 2026-10-02 19:53 UTCVendor advisory
  22. 2026-10-02 19:53 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  23. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  24. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  25. 2026-10-01 05:58 UTCEG score recompute
  26. 2026-10-01 05:58 UTCVendor advisory
  27. 2026-10-01 05:58 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  28. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  29. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  30. 2026-09-28 04:26 UTCEG score recompute
  31. 2026-09-28 04:26 UTCVendor advisory
  32. 2026-09-28 04:26 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  33. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  34. 2026-09-25 10:03 UTCEG score recompute
  35. 2026-09-25 10:03 UTCVendor advisory
  36. 2026-09-25 10:03 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  37. 2026-09-24 00:55 UTCEG score recompute
  38. 2026-09-24 00:55 UTCVendor advisory
  39. 2026-09-24 00:55 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  40. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  41. 2026-09-22 22:09 UTCEG score recompute
  42. 2026-09-22 22:09 UTCVendor advisory
  43. 2026-09-22 22:09 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  44. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  45. 2026-09-20 01:39 UTCEG score recompute
  46. 2026-09-20 01:39 UTCVendor advisory
  47. 2026-09-20 01:39 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  48. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  49. 2026-09-18 02:57 UTCEG score recompute
  50. 2026-09-18 02:57 UTCVendor advisory
  51. 2026-09-18 02:57 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  52. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  53. 2026-09-16 11:59 UTCEG score recompute
  54. 2026-09-16 11:59 UTCVendor advisory
  55. 2026-09-16 11:59 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  56. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  57. 2026-09-15 09:35 UTCEG score recompute
  58. 2026-09-15 09:35 UTCVendor advisory
  59. 2026-09-15 09:35 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  60. 2026-09-13 21:46 UTCEG score recompute
  61. 2026-09-13 21:46 UTCVendor advisory
  62. 2026-09-13 21:46 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  63. 2026-09-12 19:00 UTCEG score recompute
  64. 2026-09-12 19:00 UTCVendor advisory
  65. 2026-09-12 19:00 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  66. 2026-09-11 16:36 UTCEG score recompute
  67. 2026-09-11 16:36 UTCVendor advisory
  68. 2026-09-11 16:36 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  69. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  70. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  71. 2026-09-10 13:35 UTCEG score recompute
  72. 2026-09-10 13:35 UTCVendor advisory
  73. 2026-09-10 13:35 UTCGHSA enrichmentGHSA-8mx4-8xfc-qr43 · GitHub severity HIGH · GitHub CVSS 6.5
  74. 2026-09-09 08:44 UTCEG score recompute
  75. 2026-09-09 08:44 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-66038?
CVE-2026-66038 is a medium-severity vulnerability; its CVE record was published on July 24, 2026. 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()…
When was CVE-2026-66038 made public?
CVE-2026-66038 was made public on July 4, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on July 24, 2026. EchelonGraph's copy of the record carries a last-modified date of August 7, 2026; the record at its source may have been updated since.
Is CVE-2026-66038 actively exploited?
CVE-2026-66038 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-66038?
CVE-2026-66038 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-66038?
A fix for CVE-2026-66038 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-66038 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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