# CVE-2026-12548: Libsoup: heap out-of-bounds read in libsoup due to integer truncation

> A remote attacker can crash applications or read heap memory via an integer truncation flaw in libsoup's multipart HTTP parsing.

- **Severity:** Medium 4.2 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Jul 2026
- **Updated:** 23 Jul 2026
- **Also known as:** CLSA-2026-1788856994, CLSA-2026-1788859279, DEBIAN-CVE-2026-12548, ECHO-b6fb-3d23-a17e, GHSA-wmh6-vpqv-v8q3, SUSE-SU-2026:3973-1, SUSE-SU-2026:4023-1, SUSE-SU-2026:4105-1, UBUNTU-CVE-2026-12548, openSUSE-SU-2026:11576-1, openSUSE-SU-2026:11596-1

## What is CVE-2026-12548?

CVE-2026-12548 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A heap out-of-bounds read flaw was found in libsoup. When parsing multipart HTTP messages, an integer type mismatch between the caller and soup_headers_parse() can cause the length parameter to be incorrectly truncated, leading to a heap buffer over-read. A remote attacker could use this flaw to crash an application using libsoup or potentially disclose heap memory contents.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-12548?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libsoup` | SUSE:Linux Enterprise Module for Basesystem 15 SP7 | All versions | 3.4.4-150600.3.50.1 |
| `libsoup2` | SUSE:Linux Enterprise Module for Basesystem 15 SP7 | All versions | 2.74.3-150600.4.39.1 |
| `libsoup2` | SUSE:Linux Enterprise Server 15 SP6-LTSS | All versions | 2.74.3-150600.4.39.1 |
| `libsoup` | SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | All versions | 2.62.2-5.46.1 |
| `libsoup2` | SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | All versions | 2.74.3-150600.4.39.1 |
| `libsoup` | openSUSE:Tumbleweed | All versions | 3.6.6-8.1 |
| `libsoup2` | openSUSE:Tumbleweed | All versions | 2.74.3-22.1 |

Products: Gnome Libsoup, Redhat Enterprise Linux.

## How do I fix CVE-2026-12548?

Apply the vendor's patch.

## Is CVE-2026-12548 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-12548 exists.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2026-102556](https://insights.sbomify.com/CVE-2026-102556/): Libsoup: libsoup: heap buffer overflow from websocket pong signal type confusion (high 8.6)
- [CVE-2026-102557](https://insights.sbomify.com/CVE-2026-102557/): Libsoup: libsoup: heap buffer overflow during websocket message reassembly (high 8.6)
- [CVE-2026-102558](https://insights.sbomify.com/CVE-2026-102558/): Libsoup: libsoup: heap buffer overflow during websocket receive-buffer growth (high 8.6)
- [CVE-2026-102559](https://insights.sbomify.com/CVE-2026-102559/): Libsoup: libsoup: heap buffer overflow during websocket client-frame masking (high 8.6)
- [CVE-2026-102560](https://insights.sbomify.com/CVE-2026-102560/): Libsoup: libsoup: heap buffer overflow during outgoing permessage-deflate buffer growth (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12548 and fix it if it is affected.

What it is: CVE-2026-12548 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, 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-2026-12548 exists.

Affected product: Redhat Enterprise Linux. 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-2026-12548/ (Markdown: https://insights.sbomify.com/CVE-2026-12548/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12548
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12548
- OSV: https://osv.dev/vulnerability/CVE-2026-12548

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12548/
Summaries are generated and may contain mistakes; the official description above is the record.