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NVD / CVE Program· CNA mitre

CVE-2026-96808: In Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, valid

Noroxi assessment

Priority: Monitor (action score 29/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.11% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Flatpak Flatpak 1.18.1.

Low priority for now. Upgrade to Flatpak Flatpak 1.18.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, validated file paths by rejecting literal .. components but did not prevent symlink traversal. A malicious local user in an active local session could obtain two revokefs sessions via the system helper, create a symlink in one session pointing into the other session's directory, and retain a file descriptor through that symlink. This allowed the attacker to modify files belonging to a different revokefs session after they had been validated and imported by the system helper. In particular, an attacker could use this to tamper with ostree commit objects in the system repository after they passed signature verification, enabling root-controlled file writes to attacker-chosen paths and local root privilege escalation.

HighCVSS 7.4 · v3.1—No exploit Fix available
Published
Sep 23, 2026
Updated
Sep 24, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

29

Monitor

Low priority for now.

CVSS
29 / 40 · 7.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · mitre
7.4
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mitre). Independent of NVD's CPE analysis and usually ahead of it.

  • Flatpak Flatpak

    • before 1.18.1affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10flatpakbefore 1.16.0-9.el10_2.41.16.0-9.el10_2.4
AlmaLinux:10flatpak-develbefore 1.16.0-9.el10_2.41.16.0-9.el10_2.4
AlmaLinux:10flatpak-libsbefore 1.16.0-9.el10_2.41.16.0-9.el10_2.4
AlmaLinux:10flatpak-selinuxbefore 1.16.0-9.el10_2.41.16.0-9.el10_2.4
AlmaLinux:10flatpak-session-helperbefore 1.16.0-9.el10_2.41.16.0-9.el10_2.4
AlmaLinux:8flatpakbefore 1.12.9-7.el8_101.12.9-7.el8_10
AlmaLinux:8flatpak-develbefore 1.12.9-7.el8_101.12.9-7.el8_10
AlmaLinux:8flatpak-libsbefore 1.12.9-7.el8_101.12.9-7.el8_10
AlmaLinux:8flatpak-selinuxbefore 1.12.9-7.el8_101.12.9-7.el8_10
AlmaLinux:8flatpak-session-helperbefore 1.12.9-7.el8_101.12.9-7.el8_10
AlmaLinux:9flatpakbefore 1.12.9-4.el9_8.41.12.9-4.el9_8.4
AlmaLinux:9flatpak-develbefore 1.12.9-4.el9_8.41.12.9-4.el9_8.4
AlmaLinux:9flatpak-libsbefore 1.12.9-4.el9_8.41.12.9-4.el9_8.4
AlmaLinux:9flatpak-selinuxbefore 1.12.9-4.el9_8.41.12.9-4.el9_8.4
AlmaLinux:9flatpak-session-helperbefore 1.12.9-4.el9_8.41.12.9-4.el9_8.4
Debian:12flatpakfrom 0—
Debian:13flatpakbefore 1.16.6-1~deb13u21.16.6-1~deb13u2
Debian:14flatpakbefore 1.18.1-11.18.1-1
Red Hat:enterprise_linux:10.2flatpakbefore 0:1.16.0-9.el10_2.40:1.16.0-9.el10_2.4
Red Hat:enterprise_linux:10.2flatpak-debuginfobefore 0:1.16.0-9.el10_2.40:1.16.0-9.el10_2.4
Red Hat:enterprise_linux:10.2flatpak-debugsourcebefore 0:1.16.0-9.el10_2.40:1.16.0-9.el10_2.4
Red Hat:enterprise_linux:10.2flatpak-develbefore 0:1.16.0-9.el10_2.40:1.16.0-9.el10_2.4
Red Hat:enterprise_linux:10.2flatpak-libsbefore 0:1.16.0-9.el10_2.40:1.16.0-9.el10_2.4
Red Hat:enterprise_linux:10.2flatpak-libs-debuginfobefore 0:1.16.0-9.el10_2.40:1.16.0-9.el10_2.4

+29

Same product

flatpak: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-42472Flatpak may allow access to files outside sandbox for certain apps
    40Plan
  • CVE-2026-34078Flatpak has a complete sandbox escape leading to host file access and code execution in the host context
    38Monitor
  • CVE-2019-10063Flatpak before 1.0.8, 1.1.x and 1.2.x before 1.2.4, and 1.3.x before 1.3.1 allows a sandbox bypass.
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-90616Sep 12, 2026 · In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated
    29Monitor
  • ← EarlierCVE-2026-96807Sep 23, 2026 · In Flatpak before 1.18.1, a malicious sandboxed app can replace ~/.var/app/$appid/.ld.so with a symlink, causing regenerate_ld_cache to writ
    16Monitor
  • Later →CVE-2026-92162Oct 20, 2026 · Flatpak vulnerable to path traversal via unvalidated "arch" parameter in DeployAppstream
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Flatpak Flatpak1.18.1Vendor (CNA)
almalinux:flatpak1.12.9-4.el9_8.4 · AlmaLinux:9Package registry (OSV)
almalinux:flatpak1.16.0-9.el10_2.4 · AlmaLinux:10Package registry (OSV)
almalinux:flatpak-devel1.12.9-4.el9_8.4 · AlmaLinux:9Package registry (OSV)
almalinux:flatpak-devel1.16.0-9.el10_2.4 · AlmaLinux:10Package registry (OSV)
almalinux:flatpak-libs1.12.9-4.el9_8.4 · AlmaLinux:9Package registry (OSV)
almalinux:flatpak-libs1.16.0-9.el10_2.4 · AlmaLinux:10Package registry (OSV)
almalinux:flatpak-selinux1.12.9-4.el9_8.4 · AlmaLinux:9Package registry (OSV)
almalinux:flatpak-selinux1.16.0-9.el10_2.4 · AlmaLinux:10Package registry (OSV)
almalinux:flatpak-session-helper1.12.9-4.el9_8.4 · AlmaLinux:9Package registry (OSV)
almalinux:flatpak-session-helper1.16.0-9.el10_2.4 · AlmaLinux:10Package registry (OSV)
debian:flatpak1.16.6-1~deb13u2 · Debian:13Package registry (OSV)
red hat:flatpak0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-debuginfo0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-debugsource0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-devel0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::crbPackage registry (OSV)
red hat:flatpak-libs0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-libs-debuginfo0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-selinux0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-session-helper0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-session-helper-debuginfo0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:flatpak-tests-debuginfo0:1.12.9-4.el9_8.4 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
rocky linux:flatpak0:1.12.9-4.el9_8.4 · Rocky Linux:9Package registry (OSV)
suse:flatpak1.4.2-3.15.1 · SUSE:Linux Enterprise Server 12 SP5-LTSSPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-34078169 days apartFlatpak has a complete sandbox escape leading to host file access and code execution in the host context
    38Monitor
  • CVE-2026-9061611 days apartIn Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated
    29Monitor
  • CVE-2026-968070 days apartIn Flatpak before 1.18.1, a malicious sandboxed app can replace ~/.var/app/$appid/.ld.so with a symlink, causing regenerate_ld_cache to writ
    16Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-61 · UNIX Symbolic Link (Symlink) Following

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records