# CVE-2019-12522: Privilege escalation in n/a

> Attackers who compromise a child process can escalate privileges to root if Squid is run as root, due to improper handling of saved UIDs.

- **Severity:** Medium 4.5 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Apr 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-12522, GHSA-rwjf-j42w-jfr4, UBUNTU-CVE-2019-12522

## What is CVE-2019-12522?

CVE-2019-12522 is a medium-severity vulnerability in Squid-Cache Squid, published on 15 Apr 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An issue was discovered in Squid through 4.7. When Squid is run as root, it spawns its child processes as a lesser user, by default the user nobody. This is done via the leave_suid call. leave_suid leaves the Saved UID as 0. This makes it trivial for an attacker who has compromised the child process to escalate their privileges back to root.

Weakness: CWE-269 (Improper Privilege Management)

## Which versions are affected by CVE-2019-12522?

It affects 1 product.


Products: Squid-Cache Squid.

## How do I fix CVE-2019-12522?

No fix has been published for CVE-2019-12522 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-12522 being exploited?

There is no known exploitation of CVE-2019-12522 in the wild and no public exploit code.

## Other vulnerabilities in Squid-Cache Squid

- [CVE-2025-62168](https://insights.sbomify.com/CVE-2025-62168/): Squid vulnerable to information disclosure via authentication credential leakage in error handling (critical 10.0)
- [CVE-2025-54574](https://insights.sbomify.com/CVE-2025-54574/): Squid's URN Handling can lead to Buffer Overflow (critical 9.3)
- [CVE-2026-33526](https://insights.sbomify.com/CVE-2026-33526/): Squid vulnerable to Denial of Service in ICP Request handling (critical 9.2)
- [CVE-2026-32748](https://insights.sbomify.com/CVE-2026-32748/): Squid has Denial of Service in ICP Response handling (high 8.7)
- [CVE-2023-50269](https://insights.sbomify.com/CVE-2023-50269/): SQUID-2023:10 Denial of Service in HTTP Request parsing (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-12522 and fix it if it is affected.

What it is: CVE-2019-12522 is a medium-severity vulnerability in Squid-Cache Squid, published on 15 Apr 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-12522 in the wild and no public exploit code.

Affected product: Squid-Cache Squid. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-12522/ (Markdown: https://insights.sbomify.com/CVE-2019-12522/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-12522
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-12522
- OSV: https://osv.dev/vulnerability/CVE-2019-12522

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-12522/
Summaries are generated and may contain mistakes; the official description above is the record.