CVE-2026-102555: A flaw was found in libsoup

Q: How do I fix CVE-2026-102555?

libsoup: upgrade to 3.7.3; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2026-102555 being exploited?

CVE-2026-102555 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-102555 affect?

CVE-2026-102555 affects libsoup, enterprise linux. Severity is high (CVSS 8.2). A flaw was found in libsoup. The soup_uri_decode_data_uri() function incorrectly treated base64 data-URI payloads as NUL-terminated strings when calling g_base64_decode_inplace(). If the percent-decoded payload contained embedded NUL bytes,

Q: How urgent is CVE-2026-102555?

Priority 46/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 8.2REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2026-102555 is a high-severity flaw (CVSS 8.2) affecting libsoup, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in libsoup. The soup_uri_decode_data_uri() function incorrectly treated base64 data-URI payloads as NUL-terminated strings when calling g_base64_decode_inplace(). If the percent-decoded payload contained embedded NUL bytes, the decoded length could remain uninitialized and be used as the size of the returned GBytes. This can lead to an out-of-bounds read or application crash when processing a crafted data URI.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-09-29
Last modified	2026-10-15

Publisher (CNA): Red Hat, Inc. · Vendor: gnome · redhat

Last updated 2026-10-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-29 18:17 UTCPublished CVE record published
2026-10-15 17:17 UTCUpdated Record last modified

gnome libsoup UPGRADE

Affected: < 3.7.3

Fixed in: 3.7.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libsoup || rpm -q libsoup || libsoup --version

2. UPGRADE to 3.7.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libsoup

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libsoup

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

redhat enterprise linux MITIGATE

Affected: 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-102555?

libsoup: upgrade to 3.7.3; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-102555 being exploited?

CVE-2026-102555 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-102555 affect?

CVE-2026-102555 affects libsoup, enterprise linux. Severity is high (CVSS 8.2). A flaw was found in libsoup. The soup_uri_decode_data_uri() function incorrectly treated base64 data-URI payloads as NUL-terminated strings when calling g_base64_decode_inplace(). If the percent-decoded payload contained embedded NUL bytes,

How urgent is CVE-2026-102555?

Priority 46/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-12548 MEDIUM 4.2 MITIGATE MITIGATE A heap out-of-bounds read flaw was found in libsoup
CVE-2026-102560 HIGH 8.6 UPGRADE MITIGATE A flaw was found in libsoup
CVE-2026-102559 HIGH 8.6 UPGRADE MITIGATE A flaw was found in libsoup
CVE-2026-102558 HIGH 8.6 UPGRADE MITIGATE A flaw was found in libsoup
CVE-2026-102557 HIGH 8.6 UPGRADE MITIGATE A flaw was found in libsoup

References

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