CVE-2019-12525

CVE-2019-12525 is a critical-severity vulnerability in Squid-cache Squid with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 24% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-787.

Key facts

Description

An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote (which would satisfy its requirements), leading to a memcpy of its length minus 1.

Frequently asked questions

What is CVE-2019-12525?
An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote (which would satisfy its requirements), leading to a memcpy of its length minus 1.
How severe is CVE-2019-12525?
CVE-2019-12525 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-12525 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 24% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-12525?
CVE-2019-12525 primarily affects Squid-cache Squid. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-12525?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2019-12525 published?
CVE-2019-12525 was published on 2019-07-11 and last updated on 2026-06-17.

References

Affected products (11)

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Threat intelligence

Threat-intel indicators referencing this CVE: