CVE-2020-7663

mediumpriority · track · 32EPSS 0.046 · 92 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

4.64% (92nd) EPSS

CVSS 5 · medium

Is it mine?

28 products

Check your exposure

Who says so?

6 sources

cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-26

websocket-extensions ruby module prior to 0.1.5 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. This could be abused by an attacker to conduct Regex Denial Of Service (ReDoS) on a single-threaded server by providing a malicious payload with the Sec-WebSocket-Extensions header.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

Fixedruby4.0-rubygem-websocket-extensions-0:0.1.5-1.24.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedruby4.0-rubygem-websocket-extensions-0:0.1.5-1.24.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedruby4.0-rubygem-websocket-extensions-0:0.1.5-1.24.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedruby4.0-rubygem-websocket-extensions-0:0.1.5-1.24.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

cvss

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

8.2

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.3–8.2

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.18.2highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:Hsecondary · OSV

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · SUSE Product Security

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-400USCWE-400US

affected products (28)

Products and version ranges known to be affected.

Open Source GitLab <13.1.10all versionscert_bundDE
Open Source GitLab <13.2.8all versionscert_bundDE
Open Source GitLab <13.3.4all versionscert_bundDE
SUSE openSUSEall versionscert_bundDEcpe:/o:suse:opensuse:-
Ubuntu Linuxall versionscert_bundDEcpe:/o:canonical:ubuntu_linux:-
Open Source GitLab< 13.1.10cert_bundDE
Open Source GitLab< 13.2.8cert_bundDE
Open Source GitLab< 13.3.4cert_bundDE
n/a websocket-extensions (ruby)≤ All versions prior to 0.1.5enisa_euvdEU
Canonical Ltd. Ubuntu≤ 18.04 LTSfstec_bduRU
Canonical Ltd. Ubuntu≤ 16.04fstec_bduRU
Canonical Ltd. Ubuntu≤ 20.04 LTSfstec_bduRU
James Coglan websocket-extensions≤ 0.1.5fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.6fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.5fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.3fstec_bduRU
Novell Inc. OpenSUSE Leap≤ 15.4fstec_bduRU
Novell Inc. openSUSE Tumbleweedall versionsfstec_bduRU
Red Hat Inc. Red Hat Satellite≤ 6.8 for RHEL 7fstec_bduRU
ООО «Ред Софт» РЕД ОС≤ 7.3fstec_bduRU

showing 20 of 28

advisories (3)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2025-1087GitLab: Mehrere SchwachstellenDeutsch2020-09-02csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in GitLab ausnutzen, um einen Cross-Site Scripting oder Denial of Service Angriff durchzuführen, Sicherheitsmechanismen zu umgehen, Daten zu manipulieren oder vertrauliche Daten einzusehen.
openSUSE-SU-2026:10368-1ruby4.0-rubygem-websocket-extensions-0.1.5-1.24 on GA media2026-03-13csaf · suse_csafDE
ruby4.0-rubygem-websocket-extensions-0.1.5-1.24 on GA media
GHSA-g6wq-qcwm-j5g2Regular Expression Denial of Service in websocket-extensions (RubyGem)2020-06-05ghsa · osvUS
### Impact The ReDoS flaw allows an attacker to exhaust the server's capacity to process incoming requests by sending a WebSocket handshake request containing a header of the following form: Sec-WebSocket-Extensions: a; b="\c\c\c\c\c\c\c\c\c\c ... That is, a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. The parser takes exponential time to reject this header as invalid, and this will block the processing of any other work on the same thread. Thus if you are running a single-threaded server, such a request can render your service completely unavailable. ### Patches Users should upgrade to version 0.1.5. ### Workarounds There are no known work-arounds other than disabling any public-facing WebSocket functionality you are operating. ### References - https://blog.jcoglan.com/2020/06/02/redos-vulnerability-in-websocket-extensions/

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu osv cert_bund suse_csaf NVD CVE.org MITRE

published 2020-06-02modified 2026-06-17

references (26)

External citations — patches, advisories, analysis.

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