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CVE-2021-23351

19
FAUCET Score

CVE-2021-23351 is a Denial of Service (DoS) vulnerability affecting github.com/pires/go-proxyproto versions prior to 0.5.0, specifically impacting Fedora and go-proxyproto projects. An attacker can exploit this by sending a malformed V1 header without a newline, causing the server to exhaust memory. Rated Medium (CVSS 4.9), the attack requires high privileges (PR:H) but has low attack complexity (AC:L), leading to high availability impact (A:H). There is no evidence of active exploitation, public exploit code, or significant community discussion, and it is not listed in CISA's KEV catalog.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.5.0CPE matchmatch criteria
cpe:2.3:a:go-proxyproto_project:go-proxyproto:*:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.4MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
0.7
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.87%
Probability of exploitation in next 30 days
EPSS Percentile
77.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0187 is in the 84th percentile among its peer group of 3,565 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
gopatch availablevia ghsa
Product: github.com/pires/go-proxyprotoFixed in: 0.5.0

Vendor Advisories (1)

goGHSA-fqh4-rh59-xhvfmedium

github.com/pires/go-proxyproto denial of service vulnerability

May 18, 2021

References

github.com / pires/go-proxyproto/commit/7f48261db810703d173f27f3309a808cc2b49b8b
PatchThird Party Advisory
github.com / pires/go-proxyproto/issues/69
Third Party Advisory
github.com / pires/go-proxyproto/pull/71
PatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/4BNVGJMVI3ZTZ675EFPUHPGXCKCGSX46
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/C36IBVOZXRTWM7MGTRUTOM56P5RR74VU
snyk.io / vuln/SNYK-GOLANG-GITHUBCOMPIRESGOPROXYPROTO-1081577
Third Party Advisory