CVE-2026-34078: Flatpak has a complete sandbox escape leading to host file access and code execution in the host context
Noroxi assessment
Priority: Monitor (action score 38/100)
- 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: 1.7% (FIRST EPSS); higher than 77.4% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: flatpak flatpak 1.16.4.
Low priority for now. Upgrade to flatpak flatpak 1.16.4 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
Flatpak is a Linux application sandboxing and distribution framework. Prior to 1.16.4, the Flatpak portal accepts paths in the sandbox-expose options which can be app-controlled symlinks pointing at arbitrary paths. Flatpak run mounts the resolved host path in the sandbox. This gives apps access to all host files and can be used as a primitive to gain code execution in the host context. This vulnerability is fixed in 1.16.4.
- BDU:2026-05831
- ALSA-2026:21755
- ALSA-2026:21756
- ALSA-2026:21757
- openSUSE-SU-2026:10541-1
- RHSA-2026:21755
- RHSA-2026:21756
- RHSA-2026:21757
- RHSA-2026:23417
- RHSA-2026:23418
- RHSA-2026:23419
- RHSA-2026:23420
- RHSA-2026:25068
- RHSA-2026:25381
- RHSA-2026:30901
- RHSA-2026:35843
- RLSA-2026:21755
- RLSA-2026:21756
- RLSA-2026:21757
- SUSE-SU-2026:1511-1
- Published
- Apr 7, 2026
- Updated
- Jul 24, 2026
- EPSS
- 1.7% · 77th percentile
- CWE
- CWE-61
Report tools
Action score
38
Monitor
Low priority for now.
- CVSS
- 37 / 40 · 9.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 1.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 9.3
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Running WordPress? Scan your site free with WP Lens
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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| flatpak | flatpak | cpe:2.3:a:flatpak:flatpak |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- flatpak flatpakup to 1.16.3 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
flatpak flatpak
- < 1.16.4affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | flatpak | before 1.16.0-9.el10_2.1 | 1.16.0-9.el10_2.1 |
| AlmaLinux:10 | flatpak-devel | before 1.16.0-9.el10_2.1 | 1.16.0-9.el10_2.1 |
| AlmaLinux:10 | flatpak-libs | before 1.16.0-9.el10_2.1 | 1.16.0-9.el10_2.1 |
| AlmaLinux:10 | flatpak-selinux | before 1.16.0-9.el10_2.1 | 1.16.0-9.el10_2.1 |
| AlmaLinux:10 | flatpak-session-helper | before 1.16.0-9.el10_2.1 | 1.16.0-9.el10_2.1 |
| AlmaLinux:8 | flatpak | before 1.12.9-4.el8_10 | 1.12.9-4.el8_10 |
| AlmaLinux:8 | flatpak-devel | before 1.12.9-4.el8_10 | 1.12.9-4.el8_10 |
| AlmaLinux:8 | flatpak-libs | before 1.12.9-4.el8_10 | 1.12.9-4.el8_10 |
| AlmaLinux:8 | flatpak-selinux | before 1.12.9-4.el8_10 | 1.12.9-4.el8_10 |
| AlmaLinux:8 | flatpak-session-helper | before 1.12.9-4.el8_10 | 1.12.9-4.el8_10 |
| AlmaLinux:9 | flatpak | before 1.12.9-4.el9_8.1 | 1.12.9-4.el9_8.1 |
| AlmaLinux:9 | flatpak-devel | before 1.12.9-4.el9_8.1 | 1.12.9-4.el9_8.1 |
| AlmaLinux:9 | flatpak-libs | before 1.12.9-4.el9_8.1 | 1.12.9-4.el9_8.1 |
| AlmaLinux:9 | flatpak-selinux | before 1.12.9-4.el9_8.1 | 1.12.9-4.el9_8.1 |
| AlmaLinux:9 | flatpak-session-helper | before 1.12.9-4.el9_8.1 | 1.12.9-4.el9_8.1 |
| Alpine:v3.23 | flatpak | before 1.16.4-r0 | 1.16.4-r0 |
| Debian:12 | flatpak | before 1.14.10-1~deb12u2 | 1.14.10-1~deb12u2 |
| Debian:13 | flatpak | before 1.16.6-1~deb13u1 | 1.16.6-1~deb13u1 |
| Debian:14 | flatpak | before 1.16.4-1 | 1.16.4-1 |
| openSUSE:Tumbleweed | flatpak | before 1.16.6-1.1 | 1.16.6-1.1 |
| Red Hat:enterprise_linux_eus:10.0 | flatpak | before 0:1.16.0-5.el10_0.2 | 0:1.16.0-5.el10_0.2 |
| Red Hat:enterprise_linux_eus:10.0 | flatpak-debuginfo | before 0:1.16.0-5.el10_0.2 | 0:1.16.0-5.el10_0.2 |
| Red Hat:enterprise_linux_eus:10.0 | flatpak-debugsource | before 0:1.16.0-5.el10_0.2 | 0:1.16.0-5.el10_0.2 |
| Red Hat:enterprise_linux_eus:10.0 | flatpak-devel | before 0:1.16.0-5.el10_0.2 | 0:1.16.0-5.el10_0.2 |
+96
Same product
flatpak: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-42472Flatpak may allow access to files outside sandbox for certain apps40Plan
- 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
- CVE-2021-21261Flatpak sandbox escape via spawn portal35Monitor
Published before and after this one in the same product
- ← EarlierCVE-2023-28101Mar 16, 2023 · Flatpak metadata with ANSI control codes can cause misleading terminal output17Monitor
- ← EarlierCVE-2024-32462Apr 18, 2024 · Flatpak vulnerable to a sandbox escape via RequestBackground portal due to bad argument parsing33Monitor
- Later →CVE-2026-34079Apr 7, 2026 · Flatpak affected by arbitrary file deletion on the host filesystem34Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| flatpak flatpak | 1.16.4 · description | Vendor (CNA) |
| almalinux:flatpak | 1.12.9-4.el9_8.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:flatpak-devel | 1.12.9-4.el9_8.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:flatpak-libs | 1.12.9-4.el9_8.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:flatpak-selinux | 1.12.9-4.el9_8.1 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:flatpak-session-helper | 1.12.9-4.el9_8.1 · AlmaLinux:9 | Package registry (OSV) |
| alpine:flatpak | 1.16.4-r0 · Alpine:v3.23 | Package registry (OSV) |
| debian:flatpak | 1.14.10-1~deb12u2 · Debian:12 | Package registry (OSV) |
| opensuse:flatpak | 1.16.6-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:flatpak | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-builder | 0:1.0.0-16.el7_9 · Red Hat:rhel_els:7 | Package registry (OSV) |
| red hat:flatpak-debuginfo | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-debugsource | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-devel | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::crb | Package registry (OSV) |
| red hat:flatpak-libs | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-libs-debuginfo | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-selinux | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-session-helper | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-session-helper-debuginfo | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:flatpak-tests-debuginfo | 0:1.12.9-4.el9_8.1 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| rocky linux:flatpak | 0:1.12.9-4.el9_8.1 · Rocky Linux:9 | Package registry (OSV) |
| suse:flatpak | 1.12.8-150400.3.12.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package 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.
No history yet (it accumulates with the daily EPSS job).
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 researchersFinders, 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-2026-90616158 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-2026-96808169 days apartIn Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, valid29Monitor
- CVE-2026-96807169 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 writ16Monitor
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
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-61 · UNIX Symbolic Link (Symlink) FollowingCVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (16 more)Show less
- www.openwall.com/lists/oss-security/2026/04/09/8
- www.openwall.com/lists/oss-security/2026/04/10/14
- access.redhat.com/errata/RHSA-2026:21755
- access.redhat.com/errata/RHSA-2026:21756
- access.redhat.com/errata/RHSA-2026:21757
- access.redhat.com/errata/RHSA-2026:23417
- access.redhat.com/errata/RHSA-2026:23418
- access.redhat.com/errata/RHSA-2026:23419
- access.redhat.com/errata/RHSA-2026:23420
- access.redhat.com/errata/RHSA-2026:25068
- access.redhat.com/errata/RHSA-2026:25381
- access.redhat.com/errata/RHSA-2026:30901
- access.redhat.com/errata/RHSA-2026:35843
- access.redhat.com/security/cve/CVE-2026-34078
- bugzilla.redhat.com/show_bug.cgi?id=2456276
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34078.json
Vendor advisories and official records. Exploit/PoC links are deliberately left out.