# CVE-2026-103963: Glib-networking: unbounded tls 1.3 session ticket queue growth in glib-networking allows remote denial of service

Status: published. Published: 2026-10-30. Updated: 2026-11-04.

A flaw was found in glib-networking. When establishing connections using Transport Layer Security (TLS) version 1.3, the client-side session cache does not limit the number of session tickets retained for a single host. A malicious server can exploit this by sending excessive session ticket messages, causing the client application to continuously consume memory. This unbounded memory growth can exhaust system memory, resulting in a Denial of Service (DoS).

## Remediation

- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (glib-networking): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (glib-networking): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (glib-networking): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (glib-networking): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (glib-networking): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.34% as of 2026-11-04; percentile 27.47%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-400

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-103963 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2465656 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://gitlab.gnome.org/GNOME/glib-networking/-/merge_requests/288 (CNA: redhat)

- https://access.redhat.com/security/cve/CVE-2026-103963 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2465656 (secalert@redhat.com)

- https://gitlab.gnome.org/GNOME/glib-networking/-/merge_requests/288 (secalert@redhat.com)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-103963; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103963; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-103963; retrieved 2026-11-04; source updated Not reported

Revision: 94c7a207479a29d4bbe024697834bdcae257518a7d32ac893cfb01e4c0a9300c

Canonical: https://y2.dev/cve/CVE-2026-103963

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