Public proof of conceptFix available

CVE-2023-45539

Q: Is CVE-2023-45539 actively exploited?

Active exploitation of CVE-2023-45539 has not been confirmed. Its EPSS score was 1.5% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2023-45539?

CVE-2023-45539 has a CVSS v3 base score of 8.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.

A public proof of concept exists; no exploitation attested.

Published2023-11-28
Fixed in2.8.2
WeaknessCWE-116

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

HAProxy before 2.8.2 accepts # as part of the URI component, which might allow remote attackers to obtain sensitive information or have unspecified other impact upon misinterpretation of a path_end rule, such as routing index.html#.png to a static server.

Timeline

dates in UTC

2023-11-2820:15CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-45539?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-45539?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

HAProxy

Branch	Affected	Fixed in	Source
2.8	< 2.8.2	2.8.2	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

haproxyAlmaLinux:9all versions · fixed in 2.4.22-3.el9_3
haproxyAlmaLinux:8all versions · fixed in 1.8.27-5.el8_10.1

Full record on NVD

Fix

Update HAProxy to 2.8.2

Advisories and patches

www.mail-archive.comRelease Notes

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedslicingmelon/HAProxy-CVE-2023-45539-PoC

Sources

CISA-ADPSSVC decisionnone2024-10-15
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.18.22024-10-15
NVDCVSS 3.18.2read 2026-10-23
CISA-ADPweakness (CWE)CWE-1162024-10-15
FIRST EPSSEPSS score1.5 %2026-10-23
PoC-in-GitHubproof of concept1read 2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Published: 2023-11-28
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2023-45539?

Is CVE-2023-45539 actively exploited?

Active exploitation of CVE-2023-45539 has not been confirmed. Its EPSS score was 1.5% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-45539?

CVE-2023-45539 has a CVSS v3 base score of 8.2 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N.

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