An issue was discovered in Squid through 4.7.
Priority MEDIUM 52CWE-787Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 7 fixed, 2 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.
Summary
An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a new member to the stack. When adding a new member, there is no check to ensure that the stack won't overflow.
Why it matters now
EPSS 0.06717 93rd percentileScored 2026-11-07
Fix Partial Red Hat: 4 advisoriesRed Hat: 7 fixed, 2 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* | 3.0 – 3.5.28; 4.0 – 4.10; 5.0 – 5.0.1 | Vulnerable | squid-cache |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Debian |
| cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* | 16.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* | 18.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:* | 19.10 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* | 20.04 | Vulnerable | Canonical |
| cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* | 15.1 | Vulnerable | openSUSE |
- cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* Versions 3.0 – 3.5.28; 4.0 – 4.10; 5.0 – 5.0.1 Vulnerable ·squid-cache
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* Versions 16.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:* Versions 19.10 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* Versions 20.04 Vulnerable ·Canonical
- cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* Versions 15.1 Vulnerable ·openSUSE
Remediation
Red Hat 4 advisories
- RHSA-2020:2040 Released 2020-05-06 · Red Hat rating Importantsquid security update
- Red Hat Enterprise Linux Server (v. 7) squid-7:3.5.20-15.el7_8.1, squid-migration-script-7:3.5.20-15.el7_8.1
- Red Hat Enterprise Linux Server Optional (v. 7) squid-sysvinit-7:3.5.20-15.el7_8.1
- Red Hat Enterprise Linux Workstation (v. 7) squid-7:3.5.20-15.el7_8.1, squid-migration-script-7:3.5.20-15.el7_8.1
- Red Hat Enterprise Linux Workstation Optional (v. 7) squid-sysvinit-7:3.5.20-15.el7_8.1
- RHSA-2020:2041 Released 2020-05-06 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream (v. 8) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.aarch64::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.ppc64le::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.s390x::squid:4 +11
- RHSA-2020:2039 Released 2020-05-06 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) libecap-1.0.1-2.module+el8.1.0+4044+36416a77.aarch64::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.ppc64le::squid:4, libecap-1.0.1-2.module+el8.1.0+4044+36416a77.s390x::squid:4 +11
Show 1 more Red Hat advisories
- RHSA-2020:2038 Released 2020-05-06 · Red Hat rating Importantsquid:4 security update
- Red Hat Enterprise Linux AppStream E4S (v. 8.0) libecap-1.0.1-2.module+el8.0.0+4045+70edde92.ppc64le::squid:4, libecap-1.0.1-2.module+el8.0.0+4045+70edde92.src::squid:4, libecap-1.0.1-2.module+el8.0.0+4045+70edde92.x86_64::squid:4 +5
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2020:2041 |
| Red Hat Enterprise Linux AppStream E4S (v. 8.0) | Fixed | RHSA-2020:2038 |
| Red Hat Enterprise Linux AppStream EUS (v. 8.1) | Fixed | RHSA-2020:2039 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:2040 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:2040 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:2040 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:2040 |
Timeline
- 2026-10-02 Threatist record created from CVE-2019-12519
- 2026-10-03 Alias added: GHSA-2398-fmp4-7w9h
References
Advisory 8
- https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12519.txt
- [oss-security] 20200423 [ADVISORY] SQUID-2019:12 Multiple issues in ESI Response processing
- DSA-4682
- openSUSE-SU-2020:0623
- GLSA-202005-05
- USN-4356-1
- [debian-lts-announce] 20200710 [SECURITY] [DLA 2278-1] squid3 security update
- https://security.netapp.com/advisory/ntap-20210205-0006/
Sources
- CVE-2019-12519 · CVE Program
- CVE-2019-12519 · NVD
- FIRST EPSS
- GHSA-2398-fmp4-7w9h · GitHub Advisory Database · CC BY 4.0
- CVE-2019-12519 · Red Hat security data · CC BY 4.0
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