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CVE-2024-25617mediumCWE-182CWE-400

Denial of Service in HTTP Header parser in squid proxy

35Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5.3epss 88%
exploitation probability
88%top 1% of all CVEs
observed exploitation
nono source reports it
What the vendors declare (VEX)

Official vendor statements in CSAF/VEX format: whether their product is affected, already fixed, or ruled out — and why. These are the vendor's assertions, not Vexday's judgment.

Red HatVEX document ↗
Affected
1 product (4 components)
Red Hat Enterprise Linux 6
workaround: To mitigate this flaw in Squid versions prior to 6.5, set the request_header_max_size and reply_header_max_size configuration options to 21KB. The following lines should be added to the Squid configuration file: ~~~ request_header_max_size 21 KB…
Fixed
16 products (224 components)
Red Hat Enterprise Linux AppStream (v. 8) · Red Hat Enterprise Linux AppStream EUS (v.8.6) · Red Hat Enterprise Linux AppStream EUS (v.8.8) · Red Hat Enterprise Linux AppStream E4S (v. 8.2) · Red Hat Enterprise Linux AppStream E4S (v.8.4) · and others 11
fix ↗
In short

Squid proxy can crash when processing very large HTTP headers sent by remote clients or servers. This causes the proxy to stop working temporarily, disrupting web access for all users relying on it.

Technical detail

A Collapse of Data into Unsafe Value flaw in Squid's HTTP header parser allows remote attackers to trigger a Denial of Service by sending oversized headers exceeding request_header_max_size or reply_header_max_size limits. Affected versions prior to 6.5 use unsafe default values; exploitation requires no authentication and impacts proxy availability.

Summary generated and translated by AI from the official description.
Squid is an open source caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Collapse of Data into Unsafe Value bug ,Squid may be vulnerable to a Denial of Service attack against HTTP header parsing. This problem allows a remote client or a remote server to perform Denial of Service when sending oversized headers in HTTP messages. In versions of Squid prior to 6.5 this can be achieved if the request_header_max_size or reply_header_max_size settings are unchanged from the default. In Squid version 6.5 and later, the default setting of these parameters is safe. Squid will emit a critical warning in cache.log if the administrator is setting these parameters to unsafe values. Squid will not at this time prevent these settings from being changed to unsafe values. Users are advised to upgrade to version 6.5. There are no known workarounds for this vulnerability. This issue is also tracked as SQUID-2024:2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected products
squid-cache · squid
References
https://github.com/squid-cache/squid/commit/72a3bbd5e431597c3fdb56d752bc56b010ba3817https://github.com/squid-cache/squid/security/advisories/GHSA-h5x6-w8mv-xfprhttps://security.netapp.com/advisory/ntap-20240322-0006/