# CVE-2025-27498: AEADs/ascon-aead: Plaintext exposed in decrypt_in_place_detached even on tag verification failure

> Attackers can recover plaintext from failed AEAD decryption attempts in the RustCrypto AES-GCM library due to improper buffer clearing.

- **Severity:** Medium 5.6 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 3 Mar 2025
- **Updated:** 3 Mar 2025
- **Also known as:** GHSA-r38m-44fw-h886, UBUNTU-CVE-2025-27498

## What is CVE-2025-27498?

CVE-2025-27498 is a medium-severity vulnerability in RustCrypto AEADs, published on 3 Mar 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

aes-gcm is a pure Rust implementation of the AES-GCM. In decrypt_in_place_detached, the decrypted ciphertext (which is the correct ciphertext) is exposed even if the tag is incorrect. This is because in decrypt_inplace in asconcore.rs, tag verification causes an error to be returned with the plaintext contents still in buffer. The vulnerability is fixed in 0.4.3.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2025-27498?

2 open source packages ship an affected version, including ascon_aead.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ascon_aead` | crates.io | All versions | 0.4.3 |
| `ascon_aead` | crates.io | All versions | 0.4.3 |

## How do I fix CVE-2025-27498?

Upgrade ascon_aead to 0.4.3 or later.

## Is CVE-2025-27498 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-27498 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-27498 and fix it if it is affected.

What it is: CVE-2025-27498 is a medium-severity vulnerability in RustCrypto AEADs, published on 3 Mar 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-27498 exists.

Affected packages and fixed versions:
- ascon_aead (crates.io): affected all versions; fixed in 0.4.3
- ascon_aead (crates.io): affected all versions; fixed in 0.4.3

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-2025-27498/ (Markdown: https://insights.sbomify.com/CVE-2025-27498/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-27498
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-27498
- OSV: https://osv.dev/vulnerability/CVE-2025-27498

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-27498/
Summaries are generated and may contain mistakes; the official description above is the record.