# CVE-2016-1531: Privilege escalation in n/a

> Local attackers can gain root privileges on Exim mail servers installed with setuid root permissions via the perl_startup argument.

- **Severity:** High 7.0 (`CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 7 Apr 2016
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-1531, DSA-3517-1, GHSA-qqgw-xrxj-r5fc, UBUNTU-CVE-2016-1531

## What is CVE-2016-1531?

CVE-2016-1531 is a high-severity vulnerability in Exim Exim, published on 7 Apr 2016. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Exim before 4.86.2, when installed setuid root, allows local users to gain privileges via the perl_startup argument.

Weakness: CWE-264

## Which versions are affected by CVE-2016-1531?

It affects 1 product.


Products: Exim Exim.

## How do I fix CVE-2016-1531?

Upgrade to a fixed version.

## Is CVE-2016-1531 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-1531 exists.

Public exploit code:

- Exim 4.84-3 - Local Privilege Escalation (exploitdb)
- Exim < 4.86.2 - Local Privilege Escalation (exploitdb)
- Exim "perl_startup" Privilege Escalation (metasploit)
- Exim - 'perl_startup' Local Privilege Escalation (Metasploit) (exploitdb)
- https://github.com/h3x0v3rl0rd/CVE-2016-1531 (github_poc): https://github.com/h3x0v3rl0rd/CVE-2016-1531

## Other vulnerabilities in Exim Exim

- [CVE-2026-45185](https://insights.sbomify.com/CVE-2026-45185/): Use after free in Exim (critical 9.8)
- [CVE-2023-42115](https://insights.sbomify.com/CVE-2023-42115/): Exim AUTH Out-Of-Bounds Write Remote Code Execution Vulnerability (critical 9.8)
- [CVE-2020-28017](https://insights.sbomify.com/CVE-2020-28017/): Integer overflow in n/a (critical 9.8)
- [CVE-2020-28018](https://insights.sbomify.com/CVE-2020-28018/): Use after free in n/a (critical 9.8)
- [CVE-2020-28020](https://insights.sbomify.com/CVE-2020-28020/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-1531 and fix it if it is affected.

What it is: CVE-2016-1531 is a high-severity vulnerability in Exim Exim, published on 7 Apr 2016. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-1531 exists.

Affected product: Exim Exim. 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-2016-1531/ (Markdown: https://insights.sbomify.com/CVE-2016-1531/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-1531
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-1531
- OSV: https://osv.dev/vulnerability/CVE-2016-1531

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-1531/
Summaries are generated and may contain mistakes; the official description above is the record.