CVE-2022-35252Public exploitNetwork attack vector

Sibling-site denial via control-byte cookies

Published Sep 23, 2022 · Updated May 5, 2025

Improper cookie validation in curl 4.9 through 7.84.0 allows remote attackers to block access to sibling HTTP(S) sites. Curl_cookie_add in lib/cookie.c stores cookie names and values containing control bytes instead of rejecting them. The attack requires the cookie engine to accept a crafted cookie from one site and later send it to a sibling whose server rejects the resulting request with HTTP 400.

CVSS severity3.7
Low
EPSS probability1.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper cookie validation in curl 4.9 through 7.84.0 allows remote attackers to block access to sibling HTTP(S) sites. Curl_cookie_add in lib/cookie.c stores cookie names and values containing control bytes instead of rejecting them. The attack requires the cookie engine to accept a crafted cookie from one site and later send it to a sibling whose server rejects the resulting request with HTTP 400.

The record

CVE
CVE-2022-35252
Published
Sep 23, 2022
Updated
May 5, 2025
Vendor
curl
Product
curl
Classifications
CWE-1286, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 23, 2022CVE publishedPublication date reported by the CVE source.
  2. May 5, 2025Record 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=Fixed in curl 7.85.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

curl · curlversion=Fixed in curl 7.85.0

Published CVSS scores

3.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
3.7CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitPublished

Weakness, pattern, technique

CWE-1286Improper Validation of Syntactic Correctness of Input
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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