# CVE-2026-5119: Libsoup: libsoup: information disclosure via cleartext transmission of cookies during https tunnel establishment

> Attackers can intercept session cookies sent in cleartext during HTTPS proxy tunneling, enabling session hijacking in applications using libsoup.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N`)
- **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:** 30 Mar 2026
- **Updated:** 9 Jun 2026
- **Also known as:** ALSA-2026:13978, ALSA-2026:14087, ALSA-2026:19356, AZL-81516, CLSA-2026-1776681849, CLSA-2026-1776682775, CLSA-2026-1777035141, CLSA-2026-1777035524, CLSA-2026-1777036238, CLSA-2026-1790242017, CLSA-2026-1790242224, CLSA-2026-1790242973, CLSA-2026-1791791913, DEBIAN-CVE-2026-5119, ECHO-a910-4417-2f71, GHSA-j666-j6hj-fpc7, OESA-2026-2026, OESA-2026-2027, OESA-2026-2028, OESA-2026-2029, OESA-2026-2030, OESA-2026-2379, OESA-2026-2380, OESA-2026-2537, RHSA-2026:13978, RHSA-2026:14087, RHSA-2026:19356, RHSA-2026:21686, RHSA-2026:22316, RHSA-2026:22317, RHSA-2026:22323, RHSA-2026:22710, RHSA-2026:22716, RHSA-2026:24344, RHSA-2026:24722, RLSA-2026:13978, RLSA-2026:14087, RLSA-2026:19356, ROOT-OS-DEBIAN-12-CVE-2026-5119, ROOT-OS-DEBIAN-13-CVE-2026-5119, UBUNTU-CVE-2026-5119

## What is CVE-2026-5119?

CVE-2026-5119 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 30 Mar 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 flaw was found in libsoup. When establishing HTTPS tunnels through a configured HTTP proxy, sensitive session cookies are transmitted in cleartext within the initial HTTP CONNECT request. A network-positioned attacker or a malicious HTTP proxy can intercept these cookies, leading to potential session hijacking or user impersonation.

Weakness: CWE-319 (Cleartext Transmission of Sensitive Information)

## Which versions are affected by CVE-2026-5119?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libsoup` | AlmaLinux:8 | All versions | 2.62.3-14.el8_10 |
| `libsoup-devel` | AlmaLinux:8 | All versions | 2.62.3-14.el8_10 |
| `libsoup` | AlmaLinux:9 | All versions | 2.72.0-12.el9_7.6 |
| `libsoup` | AlmaLinux:9 | All versions | 2.72.0-16.el9_8.1 |
| `libsoup-devel` | AlmaLinux:9 | All versions | 2.72.0-12.el9_7.6 |
| `libsoup-devel` | AlmaLinux:9 | All versions | 2.72.0-16.el9_8.1 |
| `libsoup-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.62.3-14.el8_10 |
| `libsoup-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.62.3-14.el8_10 |
| `libsoup-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.62.3-14.el8_10 |
| `libsoup` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.62.3-14.el8_10 |
| `libsoup-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.62.3-14.el8_10 |
| `libsoup-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.62.3-14.el8_10 |
| `libsoup` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-12.el9_7.6 |
| `libsoup` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-16.el9_8.1 |
| `libsoup-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-12.el9_7.6 |
| `libsoup-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-16.el9_8.1 |
| `libsoup-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-12.el9_7.6 |
| `libsoup-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-16.el9_8.1 |
| `libsoup-devel` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-12.el9_7.6 |
| `libsoup-devel` | Red Hat:enterprise_linux:9::appstream | All versions | 0:2.72.0-16.el9_8.1 |
| `libsoup-debuginfo` | Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.62.3-2.el8_4.9 |
| `libsoup-debugsource` | Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.62.3-2.el8_4.9 |
| `libsoup-devel` | Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.62.3-2.el8_4.9 |
| `libsoup` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:2.62.3-2.el8_4.9 |
| `libsoup-debuginfo` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:2.62.3-2.el8_4.9 |
| `libsoup-debugsource` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:2.62.3-2.el8_4.9 |
| `libsoup-debuginfo` | Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.62.3-2.el8_6.9 |
| `libsoup-debugsource` | Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.62.3-2.el8_6.9 |
| `libsoup-devel` | Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.62.3-2.el8_6.9 |
| `libsoup` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:2.62.3-2.el8_6.9 |
| `libsoup-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:2.62.3-2.el8_6.9 |
| `libsoup-debugsource` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:2.62.3-2.el8_6.9 |
| `libsoup-debuginfo` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.62.3-3.el8_8.9 |
| `libsoup-debugsource` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.62.3-3.el8_8.9 |
| `libsoup-devel` | Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.62.3-3.el8_8.9 |
| `libsoup` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:2.62.3-3.el8_8.9 |
| `libsoup-debuginfo` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:2.62.3-3.el8_8.9 |
| `libsoup-debugsource` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:2.62.3-3.el8_8.9 |
| `libsoup` | Red Hat:rhel_e4s:9.0::appstream | All versions | 0:2.72.0-8.el9_0.10 |
| `libsoup-debuginfo` | Red Hat:rhel_e4s:9.0::appstream | All versions | 0:2.72.0-8.el9_0.10 |

Products: Gnome Libsoup, Redhat Enterprise Linux.

## How do I fix CVE-2026-5119?

Apply the vendor's patch.

## Is CVE-2026-5119 being exploited?

There is no known exploitation of CVE-2026-5119 in the wild and no public exploit code.

## 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-2026-5119 and fix it if it is affected.

What it is: CVE-2026-5119 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 30 Mar 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: There is no known exploitation of CVE-2026-5119 in the wild and no public exploit code.

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-2026-5119/ (Markdown: https://insights.sbomify.com/CVE-2026-5119/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5119
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5119
- OSV: https://osv.dev/vulnerability/CVE-2026-5119

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5119/
Summaries are generated and may contain mistakes; the official description above is the record.