# CVE-2019-20637: Information disclosure in n/a

> An attacker can read sensitive data from previous requests in the same connection due to uncleared pointers in Varnish Cache.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Apr 2020
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-20637, GHSA-h2vv-cmjp-m2w5, UBUNTU-CVE-2019-20637

## What is CVE-2019-20637?

CVE-2019-20637 is a high-severity vulnerability in Opensuse Backports Sle, published on 8 Apr 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Varnish Cache before 6.0.5 LTS, 6.1.x and 6.2.x before 6.2.2, and 6.3.x before 6.3.1. It does not clear a pointer between the handling of one client request and the next request within the same connection. This sometimes causes information to be disclosed from the connection workspace, such as data structures associated with previous requests within this connection or VCL-related temporary headers.

Weakness: CWE-212 (Improper Removal of Sensitive Information Before Storage or Transfer)

## Which versions are affected by CVE-2019-20637?

It affects 4 products.


Products: Opensuse Backports Sle, Opensuse Leap, Varnish-Cache Varnish Cache, Varnish-Software Varnish Cache.

## How do I fix CVE-2019-20637?

Upgrade to a fixed version.

## Is CVE-2019-20637 being exploited?

There is no known exploitation of CVE-2019-20637 in the wild and no public exploit code.

## Other vulnerabilities in Opensuse Backports Sle

- [CVE-2020-12641](https://insights.sbomify.com/CVE-2020-12641/): Roundcube Webmail Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2020-12640](https://insights.sbomify.com/CVE-2020-12640/): Path traversal in n/a (critical 9.8)
- [CVE-2020-8233](https://insights.sbomify.com/CVE-2020-8233/): Command injection in EdgeSwitch firmware v1.9.0 and prior (high 8.8)
- [CVE-2020-8026](https://insights.sbomify.com/CVE-2020-8026/): inn: non-root owned files (high 8.4)
- [CVE-2020-15229](https://insights.sbomify.com/CVE-2020-15229/): Path traversal and files overwrite with unsquashfs (high 8.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-20637 and fix it if it is affected.

What it is: CVE-2019-20637 is a high-severity vulnerability in Opensuse Backports Sle, published on 8 Apr 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-20637 in the wild and no public exploit code.

Affected product: Opensuse Backports Sle. 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-2019-20637/ (Markdown: https://insights.sbomify.com/CVE-2019-20637/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-20637
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-20637
- OSV: https://osv.dev/vulnerability/CVE-2019-20637

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-20637/
Summaries are generated and may contain mistakes; the official description above is the record.