CVE-2026-78663

criticalpriority · track · 0EPSS 0.006 · 50 %ileDEFRUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.62% (50th) EPSS
CVSS 9.1 · critical
Is it mine?
14 products
Check your exposure
Who says so?
3 sources
osv · cert_bund · certfr

EPSS · scored 2026-10-27

The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.

01

cvss

Technical severity, 0–10. One row per scoring source.

9.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 8.3–9.1

v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:Hsecondaryexploitability 3.9 · impact 5.2
v3.18.3highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-675US
04

affected products (14)

Products and version ranges known to be affected.

05

advisories (4)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-3841Golang Go: Mehrere SchwachstellenDeutsch2026-10-08csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Golang Go ausnutzen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Daten zu manipulieren und um Sicherheitsvorkehrungen zu umgehen.

  • BIT-golang-2026-78663Double flow control refund on HTTP/2 server streams in net/http2026-10-16vendor · osvUS

    The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.

  • CERTFR-2026-AVI-1385Multiples vulnérabilités dans les produits VMwareFrançais2026-10-26vendor · certfrFR
  • GO-2026-6612Double flow control refund on HTTP/2 server streams in net/http2026-10-08vendor · osvUS

    The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.

06

also known as (2)

Other names and identifiers for this entity.

  • BIT-golang-2026-78663osv
  • GO-2026-6612osv
07

sources

Which sources assert this record, and when.

osvcert_bundcertfrNVDCVE.orgMITRE
published 2026-10-08modified 2026-10-09
08

references (6) nvd

External citations — patches, advisories, analysis.

scry

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