CVE-2022-0711Network attack vector

Process crash via unbounded Set-Cookie2 parsing

Published Mar 2, 2022 · Updated Aug 2, 2024

Infinite-loop handling in HAProxy 2.5.1 allows remote attackers controlling a backend response to crash the proxy via Set-Cookie2. In http_manage_server_side_cookies, a failed Set-Cookie lookup clears the header context, so the next Set-Cookie2 search restarts at the beginning and repeats indefinitely. The attacker must place a crafted Set-Cookie2 header in a proxied server response; the watchdog then terminates the HAProxy process with SIGABRT, interrupting service.

CVSS severity7.5
High
EPSS probability16.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite-loop handling in HAProxy 2.5.1 allows remote attackers controlling a backend response to crash the proxy via Set-Cookie2. In http_manage_server_side_cookies, a failed Set-Cookie lookup clears the header context, so the next Set-Cookie2 search restarts at the beginning and repeats indefinitely. The attacker must place a crafted Set-Cookie2 header in a proxied server response; the watchdog then terminates the HAProxy process with SIGABRT, interrupting service.

The record

CVE
CVE-2022-0711
Published
Mar 2, 2022
Updated
Aug 2, 2024
Vendor
HAProxy Technologies
Product
HAProxy
Classifications
CWE-835, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 2, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

HAProxy Technologies · HAProxyversion=2.5.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
5.9SUSECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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