What’s Vulnerable › Vulnerabilities

CVE-2026-91096

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-28 · updated 2026-09-30
• Weakness: CWE-416

Description

In proxygen from v2024.10.28.00 until v2026.09.28.00, WebTransportImpl::terminateSessionStreams (WebTransportImpl::destroy in releases before v2025.08.18.00) failed to unregister read callbacks for streams that were no longer open before destroying them. The transport could then invoke a read callback that had been freed.

Affected products

• Facebook proxygen: from v2024.10.28.00 before v2026.09.28.00 — fixed in v2026.09.28.00

How to fix

Upgrade to a fixed version: Facebook proxygen v2026.09.28.00. Check the vendor advisory for mitigations.

References

• https://github.com/facebook/proxygen/commit/479eb5574195764e80e6cedebef669f6baa85083
• https://www.facebook.com/security/advisories/cve-2026-91096

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