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NVD / CVE Program· CNA mitre

CVE-2023-25725: HAProxy before 2.7.3 may allow a bypass of access control because HTTP/1 headers are inadvertently lost in some situations, aka "request…

CriticalCVSS 9.1 · v3.1—Proof of concept Fix available

Noroxi assessment

Priority: Monitor (action score 38/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 5.4% (FIRST EPSS); higher than 92.8% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: haproxy (AlmaLinux:9) 2.4.17-3.el9_1.2; haproxy (Debian:10) 1.8.19-1+deb10u4; haproxy (Debian:11) 2.2.9-2+deb11u4.

Low priority for now. Upgrade to haproxy (AlmaLinux:9) 2.4.17-3.el9_1.2; haproxy (Debian:10) 1.8.19-1+deb10u4; haproxy (Debian:11) 2.2.9-2+deb11u4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

HAProxy before 2.7.3 may allow a bypass of access control because HTTP/1 headers are inadvertently lost in some situations, aka "request smuggling." The HTTP header parsers in HAProxy may accept empty header field names, which could be used to truncate the list of HTTP headers and thus make some headers disappear after being parsed and processed for HTTP/1.0 and HTTP/1.1. For HTTP/2 and HTTP/3, the impact is limited because the headers disappear before being parsed and processed, as if they had not been sent by the client. The fixed versions are 2.7.3, 2.6.9, 2.5.12, 2.4.22, 2.2.29, and 2.0.31.

Published
Feb 14, 2023
Updated
Jun 17, 2026
EPSS
5.4% · 92th percentile

Report tools

JSON

Action score

38

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 5.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-25725

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
haproxyhaproxy
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux10.0
  • debian debian linux11.0
  • haproxy haproxy2.3.0 and later · before 2.4.22
  • haproxy haproxy2.5.0 and later · before 2.5.12
  • haproxy haproxybefore 2.0.31
  • haproxy haproxy2.7.0 and later · before 2.7.3
  • haproxy haproxy2.6.0 and later · before 2.6.9
  • haproxy haproxy2.1.0 and later · before 2.2.29

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:9haproxybefore 2.4.17-3.el9_1.22.4.17-3.el9_1.2
Debian:10haproxybefore 1.8.19-1+deb10u41.8.19-1+deb10u4
Debian:11haproxybefore 2.2.9-2+deb11u42.2.9-2+deb11u4
Debian:12haproxybefore 2.6.8-22.6.8-2
openSUSE:Leap Micro 5.3haproxybefore 2.4.8+git0.d1f8d41e0-150400.3.10.12.4.8+git0.d1f8d41e0-150400.3.10.1
openSUSE:Tumbleweedhaproxybefore 2.7.3+git0.1065b1000-1.12.7.3+git0.1065b1000-1.1
Red Hat:enterprise_linux:9::appstreamhaproxybefore 0:2.4.17-3.el9_1.20:2.4.17-3.el9_1.2
Red Hat:enterprise_linux:9::appstreamhaproxy-debuginfobefore 0:2.4.17-3.el9_1.20:2.4.17-3.el9_1.2
Red Hat:enterprise_linux:9::appstreamhaproxy-debugsourcebefore 0:2.4.17-3.el9_1.20:2.4.17-3.el9_1.2
Red Hat:openshift_ironic:4.13::el9python-werkzeugbefore 0:2.0.3-4.el90:2.0.3-4.el9
Red Hat:openshift_ironic:4.13::el9python3-werkzeugbefore 0:2.0.3-4.el90:2.0.3-4.el9
Red Hat:openshift:4.10::el7openshiftbefore 0:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el70:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el7
Red Hat:openshift:4.10::el7openshift-hyperkubebefore 0:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el70:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el7
Red Hat:openshift:4.10::el8haproxybefore 0:2.2.19-4.el80:2.2.19-4.el8
Red Hat:openshift:4.10::el8haproxy-debugsourcebefore 0:2.2.19-4.el80:2.2.19-4.el8
Red Hat:openshift:4.10::el8haproxy22before 0:2.2.19-4.el80:2.2.19-4.el8
Red Hat:openshift:4.10::el8haproxy22-debuginfobefore 0:2.2.19-4.el80:2.2.19-4.el8
Red Hat:openshift:4.10::el8jenkinsbefore 0:2.387.1.1680701869-1.el80:2.387.1.1680701869-1.el8
Red Hat:openshift:4.10::el8jenkins-2-pluginsbefore 0:4.10.1680703106-1.el80:4.10.1680703106-1.el8
Red Hat:openshift:4.10::el8openshiftbefore 0:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el80:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el8
Red Hat:openshift:4.10::el8openshift-hyperkubebefore 0:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el80:4.10.0-202303221742.p0.g16bcd69.assembly.stream.el8
Red Hat:openshift:4.11::el8cri-obefore 0:1.24.5-2.rhaos4.11.gitb007cb6.el80:1.24.5-2.rhaos4.11.gitb007cb6.el8
Red Hat:openshift:4.11::el8cri-o-debuginfobefore 0:1.24.5-2.rhaos4.11.gitb007cb6.el80:1.24.5-2.rhaos4.11.gitb007cb6.el8
Red Hat:openshift:4.11::el8cri-o-debugsourcebefore 0:1.24.5-2.rhaos4.11.gitb007cb6.el80:1.24.5-2.rhaos4.11.gitb007cb6.el8

+90

Same product

haproxy: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-11100In hpack_dht_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before 2.1.4, a remote attacker can write arbitrary…
    53Plan
  • CVE-2019-14241HAProxy through 2.0.2 allows attackers to cause a denial of service (ha_panic) via vectors related to htx_manage_client_side_cookies in…
    51Plan
  • CVE-2021-40346An integer overflow exists in HAProxy 2.0 through 2.5 in htx_add_header that can be exploited to perform an HTTP request smuggling attack…
    48Plan

Published before and after this one in the same product

  • ← EarlierCVE-2021-39242Aug 17, 2021 · An issue was discovered in HAProxy 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3.
    31Monitor
  • ← EarlierCVE-2022-0711Mar 2, 2022 · A flaw was found in the way HAProxy processed HTTP responses containing the "Set-Cookie2" header.
    35Monitor
  • Later →CVE-2023-0056Mar 23, 2023 · An uncontrolled resource consumption vulnerability was discovered in HAProxy which could crash the service.
    27Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:haproxy2.4.17-3.el9_1.2 · AlmaLinux:9Package registry (OSV)
debian:haproxy2.6.8-2 · Debian:12Package registry (OSV)
opensuse:haproxy2.4.8+git0.d1f8d41e0-150400.3.10.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
red hat:cri-o0:1.24.5-2.rhaos4.11.gitb007cb6.el8 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:cri-o-debuginfo0:1.24.5-2.rhaos4.11.gitb007cb6.el8 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:cri-o-debugsource0:1.24.5-2.rhaos4.11.gitb007cb6.el8 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:haproxy0:2.2.24-3.rhaos4.11.el8 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:haproxy-debugsource0:2.2.24-3.rhaos4.11.el8 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:haproxy220:2.2.24-3.rhaos4.11.el8 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:haproxy22-debuginfo0:2.2.24-3.rhaos4.11.el8 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:kernel-rt0:4.18.0-372.51.1.rt7.208.el8_6 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:kernel-rt-core0:4.18.0-372.51.1.rt7.208.el8_6 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:kernel-rt-debug0:4.18.0-372.51.1.rt7.208.el8_6 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:kernel-rt-debug-core0:4.18.0-372.51.1.rt7.208.el8_6 · Red Hat:openshift:4.11::el8Package registry (OSV)
red hat:kernel-rt-debug-debuginfo0:4.18.0-372.51.1.rt7.208.el8_6 · Red Hat:openshift:4.11::el8Package registry (OSV)
suse:haproxy2.0.31-150100.8.31.1 · SUSE:Linux Enterprise High Availability Extension 15 SP1Package registry (OSV)
suse:haproxy2.4.8+git0.d1f8d41e0-150400.3.10.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02023-08-23

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+189 d
  3. TodayNov 14, 2026+1368 d

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records