HOMEVULNERABILITIESCVE-2020-26154
CRITICAL

CVE-2020-26154

CWE-120Published: September 30, 2020· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2020-26154 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
libproxy_project1 product(s)
libproxy
openSUSE1 product(s)
leap
Source: NVD CPE · 7 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-10/msg00030.html
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-10/msg00033.html
ADVISORYhttps://bugs.debian.org/968366
ADVISORYhttps://github.com/libproxy/libproxy/pull/126
ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/11/msg00024.html
ADVISORYhttps://www.debian.org/security/2020/dsa-4800
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-10/msg00030.html
ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-10/msg00033.html
ADVISORYhttps://bugs.debian.org/968366
ADVISORYhttps://github.com/libproxy/libproxy/pull/126
ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/11/msg00024.html
ADVISORYhttps://www.debian.org/security/2020/dsa-4800

All References (16)

→
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00030.htmlIssue Tracking · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00033.htmlIssue Tracking · Third Party Advisory
→
https://bugs.debian.org/968366Issue Tracking · Third Party Advisory
→
https://github.com/libproxy/libproxy/pull/126Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/11/msg00024.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BID3HVHAF6DA3YJOFDBSAZSMR3ODNIW/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WZVZXTFMFTSML3J6OOCDBDYH474BRJSW/
→
https://www.debian.org/security/2020/dsa-4800Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00030.htmlIssue Tracking · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00033.htmlIssue Tracking · Third Party Advisory
→
https://bugs.debian.org/968366Issue Tracking · Third Party Advisory
→
https://github.com/libproxy/libproxy/pull/126Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2020/11/msg00024.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BID3HVHAF6DA3YJOFDBSAZSMR3ODNIW/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WZVZXTFMFTSML3J6OOCDBDYH474BRJSW/

Quick Facts

CVE IDCVE-2020-26154
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-120
CISA KEVNo
Affected4 vendor(s)
PublishedSep 30, 2020

Related CVEs (CWE-120)

CVE-2001-0554
10.0
CVE-1999-0385
10.0
CVE-2002-1337
10.0
CVE-2010-10016
10.0
CVE-2023-4260
10.0
CVE-2025-9962
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-26154 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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