CVE-2025-30403Network attack vector

Memory corruption via release-disabled buffer bounds check

Published Jul 11, 2025 · Updated Jul 11, 2025

Heap-buffer overflow in Meta Platforms mvfst before 2025.07.07.00 allows attackers to corrupt memory via a crafted QUIC message. BufWriter::sizeCheck used a debug-only DCHECK before push operations, so release builds could write beyond the buffer capacity. Reachability requires a QUIC session and CISA assesses user interaction as required; successful exploitation can disclose memory or interrupt the process.

CVSS severity8.1
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap-buffer overflow in Meta Platforms mvfst before 2025.07.07.00 allows attackers to corrupt memory via a crafted QUIC message. BufWriter::sizeCheck used a debug-only DCHECK before push operations, so release builds could write beyond the buffer capacity. Reachability requires a QUIC session and CISA assesses user interaction as required; successful exploitation can disclose memory or interrupt the process.

The record

CVE
CVE-2025-30403
Published
Jul 11, 2025
Updated
Jul 11, 2025
Vendor
Meta Platforms, Inc.
Product
mvfst
Classifications
CWE-122
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 11, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=v2025.03.24.00 <v2025.07.07.00

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Meta Platforms, Inc. · mvfstversion=v2025.03.24.00 <v2025.07.07.00

Published CVSS scores

8.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo