7.5

CVE-2026-44909: facebook proxygen

CVSS: 7.5v3.1HighDeferred
Published 23-07-2026Last modified 23-07-2026
Open JSON

Vulnerability summary

CVE-2026-44909 is a high (CVSS 7.5) vulnerability in facebook proxygen. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 46.3% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.57%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 23-07-2026
    PublishedVulnerability first disclosed.
  2. 23-07-2026
    Last modifiedVulnerability information updated.

Description

Proxygen lacked a generalized slow-consumer detection mechanism in its core HTTP session layer. A remote, unauthenticated attacker could exploit HTTP/2 flow-control by setting SETTINGS_INITIAL_WINDOW_SIZE to 0 or withholding WINDOW_UPDATE frames, causing the server to buffer complete response bodies in memory indefinitely for stalled streams. By opening many simultaneous streams requesting large resources while preventing the server from transmitting responses, an attacker could induce unbounded memory growth leading to service degradation, resource exhaustion, or denial of service. Versions v2017.01.16.00 through v2026.07.20.00 are affected.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.57%

Chance of exploitation in the next 30 days

Percentile

46%

Versus all other CVEs

30-day change

0.00 pp

From 0.57% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.57%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Facebook1 product
  • proxygen≥ v2017.01.16.00, < v2026.07.20.00

1 vendor · 1 product

References

1 links