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No exploitation reportedFix available

CVE-2020-15049

No exploitation reported by the sources we read.

  • Published2020-06-30
  • Fixed in5.0.3 · 4.12
  • WeaknessCWE-444

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP request with a Content-Length header containing "+\ "-" or an uncommon shell whitespace character prefix to the length field-value.

Timeline

dates in UTC
  1. 2020-06-3018:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-15049?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-15049?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Squid-cache squid
BranchAffectedFixed in
5.0≥ 5.0, < 5.0.35.0.3
4.x≥ 4.0, < 4.124.12
2.x≥ 2.0, ≤ 2.6no fix published
3.x≥ 3.1, ≤ 3.5.28no fix published
2.7= 2.7no fix published
Fedoraproject fedora
BranchAffectedFixed in
31.x= 31no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libecapAlmaLinux:8all versions · fixed in 1.0.1-2.module_el8.6.0+2741+01592ae8and 1 other package

Full record on NVD

Fix

  1. Update Squid-cache squid to 5.0.3 · 4.12

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CNACVSS 3.19.9read 2026-10-23
  • NVDCVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.06.5read 2026-10-23
  • NVDweakness (CWE)CWE-444read 2026-10-23
  • FIRST EPSSEPSS score5.7 %2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2020-06-30
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-15049?

An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP request with a Content-Length header containing "+\ "-" or an uncommon shell whitespace character prefix to the length field-value.

Is CVE-2020-15049 actively exploited?

Active exploitation of CVE-2020-15049 has not been confirmed. Its EPSS score was 5.7% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-15049?

CVE-2020-15049 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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