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Fencer Intel
high 7.5

CVE-2026-96280 json

Flatpak: flatpak: buffer overflow in oci delta stream path names on 32-bit systems

published 3mo ago modified 9h ago also EUVD-2026-88015 , GHSA-jr92-2v97-wgvc

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository flatpak/flatpak. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:1.16.0-9.el10_2.4, 0:1.18.0-2.el10_3.4
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:1.16.0-5.el10_0.6
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:1.12.9-6.el7_9
  • Red Hat Red Hat Enterprise Linux 8 0:1.12.9-7.el8_10
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:1.12.9-2.el8_4.1
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 0:1.12.9-2.el8_4.1
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:1.12.9-1.el8_6.1
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 0:1.12.9-1.el8_6.1
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:1.12.9-1.el8_8.1
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:1.12.9-1.el8_8.1
  • Red Hat Red Hat Enterprise Linux 9 0:1.12.9-4.el9_8.4, 0:1.12.9-6.el9_9.5
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:1.12.7-5.el9_2.5
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:1.12.9-3.el9_4.5
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:1.12.9-4.el9_6.5
  • flatpak Debian 13 1.16.6-1~deb13u2
  • flatpak Debian 14 1.18.1-1

debian advisories DEBIAN-CVE-2026-96280

  • flatpak RHEL 8 1.12.9-7.el8_10
  • flatpak-libs RHEL 8 1.12.9-7.el8_10
  • flatpak-selinux RHEL 8 1.12.9-7.el8_10
  • flatpak-session-helper RHEL 8 1.12.9-7.el8_10
  • flatpak RHEL 10.2 1.16.0-9.el10_2.4
  • flatpak-libs RHEL 10.2 1.16.0-9.el10_2.4
  • flatpak-selinux RHEL 10.2 1.16.0-9.el10_2.4
  • flatpak-session-helper RHEL 10.2 1.16.0-9.el10_2.4

red hat advisories RHSA-2026:80687RHSA-2026:80498RHSA-2026:80497

  • flatpak SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 1.16.6-150500.3.21.1
  • flatpak SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Desktop Applications 15 SP7 1.16.6-150600.3.12.1

suse advisories SUSE-SU-2026:5127-1SUSE-SU-2026:4944-1

  • flatpak AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak-libs AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak-selinux AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak-session-helper AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak AlmaLinux 10 1.16.0-9.el10_2.4
  • flatpak-libs AlmaLinux 10 1.16.0-9.el10_2.4
  • flatpak-selinux AlmaLinux 10 1.16.0-9.el10_2.4
  • flatpak-session-helper AlmaLinux 10 1.16.0-9.el10_2.4

almalinux advisories ALSA-2026:80497ALSA-2026:80498ALSA-2026:80687

  • flatpak Rocky Linux 10 1.16.0-9.el10_2.4
  • flatpak Rocky Linux 9 1.12.9-4.el9_8.4
  • flatpak Rocky Linux 8 1.12.9-7.el8_10

rocky linux advisories RLSA-2026:80498RLSA-2026:80497RLSA-2026:80687

Is CVE-2026-96280 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-96280 updated cvss 7.5

flatpak: flatpak: Buffer overflow in OCI delta stream path names on 32-bit systems

  • Red Hat CodeReady Linux Builder EUS (v.9.6) flatpak 1.12.9-4.el9_6.5, flatpak-session-helper 1.12.9-4.el9_6.5
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:89733
  • Red Hat Enterprise Linux AppStream (v. 8) flatpak 1.12.9-7.el8_10, flatpak-libs 1.12.9-7.el8_10, flatpak-selinux 1.12.9-7.el8_10, flatpak-session-helper 1.12.9-7.el8_10
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:80687
  • Red Hat Enterprise Linux AppStream (v. 9) flatpak 1.12.9-4.el9_8.4, flatpak 1.12.9-6.el9_9.5, flatpak-libs 1.12.9-4.el9_8.4, flatpak-libs 1.12.9-6.el9_9.5, flatpak-selinux 1.12.9-4.el9_8.4, flatpak-selinux 1.12.9-6.el9_9.5, +2 more
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:80497
  • Red Hat Enterprise Linux AppStream (v. 10) flatpak 1.16.0-9.el10_2.4, flatpak 1.18.0-2.el10_3.4, flatpak-libs 1.16.0-9.el10_2.4, flatpak-libs 1.18.0-2.el10_3.4, flatpak-selinux 1.16.0-9.el10_2.4, flatpak-selinux 1.18.0-2.el10_3.4, +2 more
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:80498
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) flatpak 1.12.9-2.el8_4.1, flatpak-libs 1.12.9-2.el8_4.1, flatpak-selinux 1.12.9-2.el8_4.1, flatpak-session-helper 1.12.9-2.el8_4.1
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:98112
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) flatpak 1.12.9-1.el8_6.1, flatpak-libs 1.12.9-1.el8_6.1, flatpak-selinux 1.12.9-1.el8_6.1, flatpak-session-helper 1.12.9-1.el8_6.1
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:95493
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) flatpak 1.12.9-1.el8_8.1, flatpak-libs 1.12.9-1.el8_8.1, flatpak-selinux 1.12.9-1.el8_8.1, flatpak-session-helper 1.12.9-1.el8_8.1
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:98127
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) flatpak 1.12.7-5.el9_2.5, flatpak-libs 1.12.7-5.el9_2.5, flatpak-selinux 1.12.7-5.el9_2.5, flatpak-session-helper 1.12.7-5.el9_2.5
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:92369
show 11 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) flatpak 1.12.9-3.el9_4.5, flatpak-libs 1.12.9-3.el9_4.5, flatpak-selinux 1.12.9-3.el9_4.5, flatpak-session-helper 1.12.9-3.el9_4.5
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:90364
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) flatpak 1.16.0-5.el10_0.6, flatpak-libs 1.16.0-5.el10_0.6, flatpak-selinux 1.16.0-5.el10_0.6, flatpak-session-helper 1.16.0-5.el10_0.6
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:92221
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) flatpak 1.12.9-4.el9_6.5, flatpak-libs 1.12.9-4.el9_6.5, flatpak-selinux 1.12.9-4.el9_6.5, flatpak-session-helper 1.12.9-4.el9_6.5
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:89733
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) flatpak 1.12.9-2.el8_4.1, flatpak-libs 1.12.9-2.el8_4.1, flatpak-selinux 1.12.9-2.el8_4.1, flatpak-session-helper 1.12.9-2.el8_4.1
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:98112
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) flatpak 1.12.9-1.el8_6.1, flatpak-libs 1.12.9-1.el8_6.1, flatpak-selinux 1.12.9-1.el8_6.1, flatpak-session-helper 1.12.9-1.el8_6.1
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:95493
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) flatpak 1.12.9-1.el8_8.1, flatpak-libs 1.12.9-1.el8_8.1, flatpak-selinux 1.12.9-1.el8_8.1, flatpak-session-helper 1.12.9-1.el8_8.1
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:98127
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) flatpak 1.12.9-4.el9_8.4, flatpak 1.12.9-6.el9_9.5, flatpak-session-helper 1.12.9-4.el9_8.4, flatpak-session-helper 1.12.9-6.el9_9.5
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:80497
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) flatpak-devel 1.16.0-9.el10_2.4, flatpak-devel 1.18.0-2.el10_3.4, flatpak-debuginfo 1.16.0-9.el10_2.4, flatpak-debuginfo 1.18.0-2.el10_3.4, flatpak-debugsource 1.16.0-9.el10_2.4, flatpak-debugsource 1.18.0-2.el10_3.4, +6 more
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:80498
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) flatpak-devel 1.16.0-5.el10_0.6, flatpak-debuginfo 1.16.0-5.el10_0.6, flatpak-debugsource 1.16.0-5.el10_0.6, flatpak-libs-debuginfo 1.16.0-5.el10_0.6, flatpak-tests-debuginfo 1.16.0-5.el10_0.6, flatpak-session-helper-debuginfo 1.16.0-5.el10_0.6
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:92221
  • Red Hat Enterprise Linux CRB (v. 8) flatpak 1.12.9-7.el8_10, flatpak-session-helper 1.12.9-7.el8_10
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:80687
  • Red Hat Enterprise Linux Server (v. 7 ELS) flatpak 1.12.9-6.el7_9, flatpak-libs 1.12.9-6.el7_9 Red Hat Enterprise Linux Server Optional (v. 7 ELS) flatpak-builder 1.0.0-18.el7_9
    fixed: vendor fix “Only install applications from trusted OCI registries. Flatpak remotes using the default OSTree transport are not affected.” RHSA-2026:99010

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
last mo.

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of flatpak/flatpak published their own advisory on GitHub. Reviewed sources take precedence over it.