How severe is CVE-2020-26154?

CVE-2020-26154 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-2020-26154 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-26154?

CVE-2020-26154 primarily affects Libproxy Project Libproxy. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-26154?

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-2020-26154 published?

CVE-2020-26154 was published on 2020-09-30 and last updated on 2026-06-17.

CVE-2020-26154

CVE-2020-26154 is a critical-severity vulnerability in Libproxy Project Libproxy with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 6.8
EPSS exploit prediction: 4% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Libproxy Project Libproxy
Published: 2020-09-30
Last modified: 2026-06-17

Description

url.cpp in libproxy through 0.4.15 is prone to a buffer overflow when PAC is enabled, as demonstrated by a large PAC file that is delivered without a Content-length header.

Frequently asked questions

What is CVE-2020-26154?: url.cpp in libproxy through 0.4.15 is prone to a buffer overflow when PAC is enabled, as demonstrated by a large PAC file that is delivered without a Content-length header.
How severe is CVE-2020-26154?: CVE-2020-26154 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-2020-26154 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-26154?: CVE-2020-26154 primarily affects Libproxy Project Libproxy. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-26154?: 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-2020-26154 published?: CVE-2020-26154 was published on 2020-09-30 and last updated on 2026-06-17.

References

Affected products (7)

cpe:2.3:a:libproxy_project:libproxy:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*

More vulnerabilities in Libproxy Project Libproxy

CVE-2012-4505 — Critical (CVSS 10.0): Heap-based buffer overflow in the px_pac_reload function in lib/pac.c in libproxy 0.2.x and 0.3.x allows remote servers…
CVE-2012-4504 — Critical (CVSS 10.0): Stack-based buffer overflow in the url::get_pac function in url.cpp in libproxy 0.4.x before 0.4.9 allows remote…
CVE-2020-25219 — High (CVSS 7.5): url::recvline in url.cpp in libproxy 0.4.x through 0.4.15 allows a remote HTTP server to trigger uncontrolled recursion…
CVE-2012-5580 — High (CVSS 7.5): Format string vulnerability in the print_proxies function in bin/proxy.c in libproxy 0.3.1 might allow…

All CVEs affecting Libproxy Project Libproxy →

Other CWE-120 (Classic Buffer Overflow) vulnerabilities

CVE-2025-48611 — Critical (CVSS 10.0): In DeviceId of DeviceId.java, there is a possible desync in persistence due to a missing bounds check. This could lead…
CVE-2026-24823 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in FASTSHIFT…
CVE-2026-24810 — Critical (CVSS 10.0): Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in rethinkdb (src/cjson modules).…
CVE-2026-24800 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in tildearrow…
CVE-2025-9962 — Critical (CVSS 10.0): A buffer overflow vulnerability in Novakon P series allows attackers to gain root permission without prior…
CVE-2010-10016 — Critical (CVSS 10.0): BS.Player version 2.57 (build 1051) contains a vulnerability in its playlist import functionality. When processing .m3u…

Browse all CWE-120 (Classic Buffer Overflow) vulnerabilities →