Story · 1 source · 2 articlesfirst Sep 22, 21:52 UTCupdated Sep 23, 18:35 UTC (3d ago)

Flatpak 1.18.1 fixes receive CVE identifiers from MITRE and Red Hat after GitHub CNA non-response

mediumVulnerabilityimportance 38CVE-2026-90616 CVE-2026-96275 CVE-2026-96276 CVE-2026-96279 CVE-2026-92162 CVE-2026-96807 CVE-2026-96808

What's new: The latest development in the story is the 2026-09-23 oss-security post in which MITRE assigned CVE-2026-96807 and CVE-2026-96808 (mapped to GHSA-99wv-m8rp-g58x and GHSA-qrwq-7qwx-q9rp respectively). Relative to the previous story summary, no new reports or facts were added; this merge consolidates the same two posts, retaining the caveat that the sources do not confirm the pending IDs are fully…

Merged summary · glm-5.3 · rewritten as coverage arrives

Flatpak maintainer Simon McVittie published CVE IDs for most vulnerabilities fixed in Flatpak 1.18.1 after GitHub's CNA failed to respond, and MITRE assigned two further IDs on 23 September; some identifiers were still pending and no impact details were given.

Flatpak maintainer Simon McVittie announced on oss-security on 2026-09-22 that CVE identifiers had been obtained for most of the vulnerabilities fixed in Flatpak 1.18.1, after requests to GitHub as CNA drew no response and were redirected to MITRE and Red Hat. The published IDs are CVE-2026-90616, CVE-2026-96275, CVE-2026-96276, CVE-2026-96279, and CVE-2026-92162; at that time two identifiers remained pending, including MITRE candidate reference CAN-2026-2052453, with others requested from Red Hat. On 2026-09-23 McVittie reported that MITRE assigned CVE-2026-96808, mapping to GHSA-qrwq-7qwx-q9rp, and CVE-2026-96807, mapping to GHSA-99wv-m8rp-g58x, both covering issues fixed in Flatpak 1.18.1. The two posts do not contradict each other, but neither explicitly states that these two IDs close out the earlier pending set or resolve CAN-2026-2052453. Neither message describes impact or exploitation; both are administrative CVE-mapping follow-ups.

Flatpak 1.18.1 fixed multiple vulnerabilities; CVE IDs for most of them were announced on 2026-09-22 by maintainer Simon McVittie on oss-security.
Requests for IDs initially went to GitHub as CNA before unembargoing, but drew no response, so they were redirected to MITRE and Red Hat.
IDs assigned via that route: CVE-2026-90616, CVE-2026-96275, CVE-2026-96276, CVE-2026-96279, CVE-2026-92162.
As of 2026-09-22, two identifiers remained pending: one from MITRE (candidate ref CAN-2026-2052453) and others requested from Red Hat.
On 2026-09-23, MITRE assigned CVE-2026-96808 (GHSA-qrwq-7qwx-q9rp) and CVE-2026-96807 (GHSA-99wv-m8rp-g58x) for issues fixed in Flatpak 1.18.1.
Neither report states whether the 23 September IDs resolve the pending identifiers or CAN-2026-2052453.
Neither report describes impact or exploitation; both are administrative CVE-mapping announcements.

VendorsFlatpak

ProductsFlatpak

OrganizationsFlatpak Simon McVittie MITRE Red Hat

Coverage timelineoldest first · each row is one article

Sep 22, 21:52 UTC · 4d ago
oss-security· 38
Re: Flatpak 1.18.1 fixes multiple vulnerabilities
Simon McVittie disclosed CVE identifiers for multiple vulnerabilities fixed in Flatpak 1.18.1, with two IDs still pending from MITRE.
Sep 23, 18:35 UTC · 3d ago
oss-security· 32
Re: Flatpak 1.18.1 fixes multiple vulnerabilities
MITRE assigned CVE-2026-96808 and CVE-2026-96807 to Flatpak flaws fixed in 1.18.1.

Vulnerabilities in this storyAll →

CVE-2026-906167.4—
Symlink escape in Flatpak before 1.18.1 lets sandboxed apps read/write host files
published 14d ago· Flatpak
CVE-2026-92162——
published — PoC

CVE	Vulnerability	CVSS	EPSS	Flags	Affected	Exposure	Published
CVE-2026-90616	Symlink escape in Flatpak before 1.18.1 lets sandboxed apps read/write host files Flatpak versions before 1.18.1 fail to apply symlink protection when creating per-app data directories such as /var/cache, /var/data, /var/config, and /var/tmp inside each sandbox on every app launch. Because components of the host-side mount path (e.g., ~/.var/app/APP_ID/cache/tmp) are attacker-controlled, a malicious sandboxed app can plant symlinks that redirect where these directories are bind-mounted. The path is passed through bwrap --bind to the kernel, which follows symlinks, so the attacker-chosen target on the host becomes mounted inside the sandbox. This yields arbitrary file read and write access on the host, which can be escalated to arbitrary code execution outside the sandbox (CVSS 3.1: 7.4, CWE-61; a distinct issue from CVE-2026-76925). Any Linux system running Flatpak before 1.18.1 is affected, but exploitation requires the victim to have installed the attacker's malicious Flatpak app; no public PoC, KEV listing, or in-the-wild exploitation is known. Do: Upgrade to Flatpak 1.18.1 or later as soon as your distribution ships it, applying distro security backports where 1.18.1 is not yet packaged. Until patched, restrict installs to trusted remotes and verified Flathub publishers and remove any Flatpak apps from unverified sources. Inspect ~/.var/app/APP_ID/ directories for unexpected symlinks pointing outside the app's data tree, which would indicate a malicious app attempting this technique.	7.4	—		Flatpak before 1.18.1 (all versions < 1.18.1)	masstens of millions of Linux desktops and devices potentially affected (Flatpak is preinstalled on major distributions and the Steam Deck)	14d ago
CVE-2026-92162	NVD description · AI analysis pending	—	—	PoC	—	—	—
CVE-2026-96275	Path Traversal Leading to Root Write in Flatpak CVE-2026-96275 is a path traversal vulnerability in Flatpak's extract_extra_data() function that allows writing attacker-controlled content to arbitrary locations on the host filesystem. The flaw is triggered when processing a malicious or compromised Flatpak repository that uses specially crafted `files/extra` paths (via symlinks) and `xa.extra-data-sources` blob names containing `..` traversal sequences. On system-wide Flatpak installations, this write operation occurs with root privileges, leading to a complete system compromise. The vulnerability affects all Flatpak versions prior to the fix in 1.18.1, and there are no known public exploits or in-the-wild exploitation as of the advisory. Do: Upgrade to Flatpak version 1.18.1 or later, as this version contains the fix for the path traversal vulnerability. Users should only install Flatpak applications from trusted repositories to avoid exposure to malicious repository definitions. System administrators should check for any unauthorized or suspicious Flatpak repositories configured on their hosts.	8.8	—		Flatpak Project Flatpak versions < 1.18.1	—	3d ago
CVE-2026-96276 +2 related CVEs CVE-2026-96808 CVE-2026-96807	Path traversal in Flatpak build-init SDK extensions writes files outside build directory Flatpak's build tooling contains a path traversal flaw (CWE-22) in how SDK extension points are handled: when a developer runs `flatpak build-init --writable-sdk --sdk-extension` with a malicious or compromised SDK container, the extension point's `directory` field is resolved by a function that permits `..` traversal. This lets the SDK's author cause attacker-chosen files to be written outside the intended build working directory on the developer's machine. Because arbitrary files can be planted (for example into home-directory configuration), this can plausibly escalate to code execution in the developer's context during subsequent builds or logins. Only developers building with writable SDKs and extension points are exposed — end users who merely run installed Flatpak apps are not affected by this code path. No public proof-of-concept exists and no exploitation has been reported; a fix ships in Flatpak 1.18.1 per the release announcement. Do: Update Flatpak to 1.18.1 or your distribution's patched maintenance release. Only run build-init with writable SDKs from trusted sources (official freedesktop runtimes or reputable SDK providers), and inspect any SDK extension point declarations for `..` sequences before building. If you have built against third-party SDKs, audit your build machines for unexpected files created outside the build directory (e.g., in your home or git config) and rotate credentials used in those environments.	9.8 group max	—		Flatpak project (freedesktop.org) Flatpak Affected version range not specified in the advisory; fix available in 1.18.1 per the Flatpak 1.18.1 release announcement
CVE-2026-96279	NVD description · AI analysis pending	—	—		—	—	—