Gstreamer: gstreamer: use-after-free in gstreamer core buffer value deserialization
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
Do first: Workaround: Restrict access to network-facing GStreamer Data Protocol receivers to trusted peers, and avoid passing externally supplied strings to gst_caps_from_string() or gst_structure_from_string() until an update is available.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 40/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Gstreamer multimedia framework contains a use-after-free flaw in its core buffer value deserialization that can be triggered remotely, without logging in or any user action, by crafted serialized data sent to a network-facing GStreamer Data Protocol receiver or parsed by an application handling untrusted caps or structure data. An attacker can crash the affected application (denial of service), and further impact has not been established.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
A use-after-free flaw was found in GStreamer core buffer value deserialization. When serialized buffer text contains an invalid character, an error path frees a mapped buffer before unmapping it. Applications that parse untrusted caps or structure data can reach a freed-buffer read and may crash. A network-facing GStreamer Data Protocol receiver can process such caps data without user interaction; further impact has not been established.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach10/20Shipped in major Linux distributions
- Severity7.5/10CVSS 7.5
- No patch5/5No patch listed yet
What would change the score
- Would score about 85 if added to CISA KEV
- Would score about 80 if CISA's SSVC rates exploitation active
- Would score about 45 if advisories confirm default setups are exposed
What to do
Workaround: Restrict access to network-facing GStreamer Data Protocol receivers to trusted peers, and avoid passing externally supplied strings to gst_caps_from_string() or gst_structure_from_string() until an update is available.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-125704 (Gstreamer: gstreamer: use-after-free in gstreamer core buffer value deserialization), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-125704 (entry last updated 2026-11-10): Affected: - Red Hat Red Hat Enterprise Linux 10: version range not reported - Red Hat Red Hat Enterprise Linux 7: version range not reported - Red Hat Red Hat Enterprise Linux 8: version range not reported - Red Hat Red Hat Enterprise Linux 9: version range not reported Fixed versions: none listed yet. Conditions (all must be true for the bug to be hit): - An application parses untrusted caps or structure data. (source: https://access.redhat.com/security/cve/cve-2026-125704) - Crafted serialized buffer data contains an invalid character, which triggers the error path. (source: https://access.redhat.com/security/cve/cve-2026-125704) - A network-facing GStreamer Data Protocol receiver processes such data. (source: https://access.redhat.com/security/cve/cve-2026-125704) Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: network access, no login, no user action. Workaround: Restrict access to network-facing GStreamer Data Protocol receivers to trusted peers, and avoid passing externally supplied strings to gst_caps_from_string() or gst_structure_from_string() until an update is available. (source: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11583.patch) CISA KEV: CVE-2026-125704 is not listed as of cve.now's last read. This KEV status is for CVE-2026-125704 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://bugzilla.redhat.com/show_bug.cgi?id=2569128 - https://access.redhat.com/security/cve/CVE-2026-125704 - https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11583.patch - https://gstreamer.freedesktop.org/security/sa-2026-0028.html - https://access.redhat.com/security/cve/cve-2026-125704 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-125704 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-125704.
Timeline
- CVE published
- First seen by cve.now
- Record last updated
Affected versions
- gstreamer1
Version range not reported
- gstreamer1
Version range not reported
- gstreamer1
Version range not reported
- gstreamer1
Version range not reported
Evidence 6
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Write-ups · 1
Establishes: Technical detail and context.
- Report
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-125704
Is CVE-2026-125704 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
When crafted serialized buffer data contains an invalid character, an error path frees a mapped buffer before unmapping it. Later access to that freed memory can crash or terminate the parsing process, which is a denial of service. Information disclosure and code execution were not demonstrated.Source: access.redhat.com, gitlab.freedesktop.org
Am I affected, and how do I check?
The advisory lists Red Hat Enterprise Linux 7, 8, 9 and 10 as affected products, with no version ranges given. The bug needs an application that parses untrusted caps or structure data, and a network-facing GStreamer Data Protocol receiver that processes such data. To check a system, look at the installed GStreamer package version and whether an application uses gst_caps_from_string() or gst_structure_from_string() on external input.Source: access.redhat.com, gitlab.freedesktop.org
How do I fix CVE-2026-125704?
No fixed version is listed in the facts, so no upgrade target can be named from this source. Watch the Red Hat advisory for a patched package and apply it when it is released.Source: access.redhat.com, gitlab.freedesktop.org
What if there's no patch?
Restrict access to network-facing GStreamer Data Protocol receivers to trusted peers. Avoid passing externally supplied strings to gst_caps_from_string() or gst_structure_from_string() until an update is available.Source: access.redhat.com, gitlab.freedesktop.org