CVE-2026-57094 — Microsoft Windows Media Foundation Remote Code Execution Vulnerability

Executive Summary

Heap-based buffer overflow in Microsoft Windows Media Foundation allows an unauthorized attacker to execute code over a network.

Overview

8.8

CVSS HIGH

Critical

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Remote Code Execution

Weakness CWE-122: Heap-based Buffer Overflow

Released Jul 14 2026

Last Updated Jul 14 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.00829 — 0.54385 percentile

NVD CVSS 8.8 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

Required

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 7.7

EPSS Score

0.00829

probability of exploitation in the next 30 days

0.54385 percentile - updated 2026-08-14

View on FIRST.org

Affected Products

23 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1607 for 32-bit Systems	`5099535 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1607 for x64-based Systems	`5099535 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for 32-bit Systems	`5099538 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 1809 for x64-based Systems	`5099538 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 21H2 for 32-bit Systems	`5099539 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 21H2 for ARM64-based Systems	`5099539 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 21H2 for x64-based Systems	`5099539 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 22H2 for 32-bit Systems	`5099539 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 22H2 for ARM64-based Systems	`5099539 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 10 Version 22H2 for x64-based Systems	`5099539 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 11 Version 24H2 for ARM64-based Systems	`5101650 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 11 Version 24H2 for x64-based Systems	`5101650 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 11 Version 25H2 for ARM64-based Systems	`5101650 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 11 Version 25H2 for x64-based Systems	`5101650 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 11 Version 26H1 for ARM64-based Systems	`5101649 (Security Update)`	Critical	Remote Code Execution	Yes
Windows 11 version 26H1 for x64-based Systems	`5101649 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2016	`5099535 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2016 (Server Core installation)	`5099535 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019	`5099538 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2019 (Server Core installation)	`5099538 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2022	`5099540 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2025	`5099536 (Security Update)`	Critical	Remote Code Execution	Yes
Windows Server 2025 (Server Core installation)	`5099536 (Security Update)`	Critical	Remote Code Execution	Yes

Patches

7 patches

Article	Type	Restart
`5099535`	Security Update	Yes
`5099538`	Security Update	Yes
`5099539`	Security Update	Yes
`5101650`	Security Update	Yes
`5101649`	Security Update	Yes
`5099540`	Security Update	Yes
`5099536`	Security Update	Yes

Patch Diff

ghidriff · mfds.dll (KB5101650)

Heap-based buffer overflow (CWE-122, with CWE-125 out-of-bounds read) in Windows Media Foundation mfds.dll HEVC short-term reference-picture-set parser, remote code execution when a user opens a crafted media file (Critical, AV:N, UI:R, CVSS 8.8). CHEVCParser::parseShortTermRefPicSet fills a ReferencePictureSet structure (0x140 bytes; DeltaPOC array at +0x20, per-entry used flags at +0xA0, max 16 entries) via two branches: an explicit branch (bitstream) and an inter-RPS prediction branch (derived from a previously parsed set). PRE: the explicit branch enforced the 16-entry limit (if count > 0x10 return 0), but the inter-RPS prediction branch performed NO bound on its write index - it iterated the referenced set's entry count and wrote DeltaPOC[idx] (+0x20) and used[idx] (+0xA0) with an index never compared to 16, then stored the resulting count as the next set's bound. A crafted HEVC bitstream can drive the prediction branch to write past the 0x140-byte ReferencePictureSet - a heap overflow (plus OOB reads of the referenced set). Because a user need only open a crafted media file, this is an RCE primitive (Critical 8.8). Diff of mfds.dll 10.0.26100.8328 -> .8875 (Jul 14 2026, KB5101650, 24H2) confirms the fix: gated behind CFR flag Feature_1136894267 (the flag present in the analysed ghidriff; an alternate decompilation cites Feature_1405329723), a new bounded accessor ReferencePictureSet::setDeltaPOC writes only when idx < 0x10, the prediction branch routes all DeltaPOC/used writes through it, and the parser rejects an over-limit predicted count (count >= 0x10 return 0). Mechanism cross-checked against an independent decompilation writeup (functions/offsets match; only the feature-flag ID differs by tool).

Pre-patch version 10.0.26100.8328 Download

Post-patch version 10.0.26100.8875 Download

Function	Address	Change	Note
`ReferencePictureSet::setDeltaPOC (added)`	`code change`	added (bounded accessor, CFR-gated)	New setter: if (!Feature_1136894267 \|\| idx < 0x10) (this + idx4 + 0x20) = val; enforces the 16-entry bound on DeltaPOC writes that the inter-RPS prediction branch previously lacked.
`CHEVCParser::parseShortTermRefPicSet`	`code change`	code (inter-RPS prediction branch now bounded, CFR-gated)	Pre: the prediction branch wrote DeltaPOC[idx] (+0x20) and used[idx] (+0xA0) with an index never compared to 16 (explicit branch checked > 0x10). Post (Feature_1136894267): routes writes through setDeltaPOC and rejects an over-limit predicted count (count >= 0x10 return 0).
`Feature_1136894267`	`gate`	added (CFR gate)	CFR flag gating the bounded RPS write path; original unbounded prediction branch ships when disabled. (An independent writeup cites Feature_1405329723 for the same fix; the analysed ghidriff shows Feature_1136894267.)

View full diff report View RCA report

Attack Path

A crafted HEVC inter-RPS prediction set writes past the 0x140-byte ReferencePictureSet, overflowing the heap

Derived from the patch delta: the checks added by the vendor identify which fields crossed a trust boundary unvalidated. Reachability and privilege are taken from the call chain in the RCA report.

Exploits & PoC

No public exploit or PoC has been linked for this CVE yet. When available, references are sourced from public repositories and may be unverified or non-functional — review carefully before use.

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

yhw & txz

References

MSRC Advisory MITRE NVD