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CVE-2019-11940

29
FAUCET Score

CVE-2019-11940 is a critical use-after-free vulnerability affecting Facebook's Proxygen library (versions v0.29.0 to v2017.04.03.00). It arises from improper handling of HPACK header table resize operations within the HTTP/2 protocol, leading to a corrupted state and undefined behavior. With a CVSS score of 9.8, this vulnerability is highly severe, allowing unauthenticated attackers to achieve high confidentiality, integrity, and availability impacts over the network with low attack complexity. Despite its critical nature, there is no evidence of active exploitation, public exploit code, or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
>= 0.29.0, <= 2017.04.03.00CPE matchmatch criteria
cpe:2.3:a:facebook:proxygen:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.36%
Probability of exploitation in next 30 days
EPSS Percentile
68.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0136 is in the 55th percentile among its peer group of 36,833 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / facebook/proxygen/commit/f43b134cc5c19d8532e7fb670a1c02e85f7a8d4f
PatchThird Party Advisory
facebook.com / security/advisories/cve-2019-11940
Third Party Advisory