# CVE-2021-43823: Side-channel attack in Sourcegraph

> Authenticated attackers can guess private source code strings, such as API keys, via side-channel attacks in Saved Searches and Code Monitoring features.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Dec 2021
- **Updated:** 4 Aug 2024

## What is CVE-2021-43823?

CVE-2021-43823 is a medium-severity vulnerability in sourcegraph, published on 13 Dec 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Sourcegraph is a code search and navigation engine. Sourcegraph prior to version 3.33.2 is vulnerable to a side-channel attack where strings in private source code could be guessed by an authenticated but unauthorized actor. This issue affects the Saved Searches and Code Monitoring features. A successful attack would require an authenticated bad actor to create many Saved Searches or Code Monitors to receive confirmation that a specific string exists. This could allow an attacker to guess formatted tokens in source code, such as API keys. This issue was patched in version 3.33.2 and any future versions of Sourcegraph. We strongly encourage upgrading to secure versions. If you are unable to, you may disable Saved Searches and Code Monitors.

Weakness: CWE-203 (Observable Discrepancy), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2021-43823?

It affects 1 product.


Products: Sourcegraph Sourcegraph.

## How do I fix CVE-2021-43823?

No fix has been published for CVE-2021-43823 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-43823 being exploited?

There is no known exploitation of CVE-2021-43823 in the wild and no public exploit code.

## Other vulnerabilities in sourcegraph

- [CVE-2022-41943](https://insights.sbomify.com/CVE-2022-41943/): Incorrect default permissions found in Sourcegraph (critical 9.0)
- [CVE-2022-23642](https://insights.sbomify.com/CVE-2022-23642/): Code Injection in Sourcegraph (high 8.8)
- [CVE-2022-41942](https://insights.sbomify.com/CVE-2022-41942/): Sourcegraph vulnerable to Comand Injection via gitserver (high 7.9)
- [CVE-2022-29171](https://insights.sbomify.com/CVE-2022-29171/): Remote Code Execution in sourcegraph (medium 6.6)
- [CVE-2022-23643](https://insights.sbomify.com/CVE-2022-23643/): Side-channel attack in Sourcegraph Code Monitors (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-43823 and fix it if it is affected.

What it is: CVE-2021-43823 is a medium-severity vulnerability in sourcegraph, published on 13 Dec 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-43823 in the wild and no public exploit code.

Affected product: sourcegraph. 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-2021-43823/ (Markdown: https://insights.sbomify.com/CVE-2021-43823/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43823
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43823
- OSV: https://osv.dev/vulnerability/CVE-2021-43823

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43823/
Summaries are generated and may contain mistakes; the official description above is the record.