A vulnerability was discovered in gdm before 3.31.4.
A vulnerability was discovered in gdm before 3.31.4. When timed login is enabled in configuration, an attacker could bypass the lock screen by selecting the timed login user and waiting for the timer to expire, at which time they would gain access to the logged-in user's session.
- Published
- Feb 6, 2019
- Updated
- Jun 16, 2026
- EPSS
- 0.5% · 41th percentile
- CWE
- CWE-287
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Report tools
Action score
25
Monitor
Low priority for now.
- CVSS
- 25 / 40 · 6.4 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CNA vs NVD score
- NVD
- 6.4
- CNA · redhat
- 6.3
- 0.1 point gap
CVSS:3.0/AV:P/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| gnome | gnome display manager | cpe:2.3:a:gnome:gnome_display_manager |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux18.04
- canonical ubuntu linux18.10
- gnome gnome display managerbefore 3.31.4
- redhat enterprise linux7.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
The Gnome Projectr gdm
- 3.31.4affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | accountsservice-devel | before 0.6.50-8.el8 | 0.6.50-8.el8 |
| AlmaLinux:8 | baobab | before 3.28.0-4.el8 | 3.28.0-4.el8 |
| AlmaLinux:8 | clutter | before 1.26.2-8.el8 | 1.26.2-8.el8 |
| AlmaLinux:8 | clutter-devel | before 1.26.2-8.el8 | 1.26.2-8.el8 |
| AlmaLinux:8 | clutter-doc | before 1.26.2-8.el8 | 1.26.2-8.el8 |
| AlmaLinux:8 | gjs-devel | before 1.56.2-4.el8 | 1.56.2-4.el8 |
| AlmaLinux:8 | gnome-menus | before 3.13.3-11.el8 | 3.13.3-11.el8 |
| AlmaLinux:8 | gnome-menus-devel | before 3.13.3-11.el8 | 3.13.3-11.el8 |
| AlmaLinux:8 | gnome-tweaks | before 3.28.1-7.el8 | 3.28.1-7.el8 |
| AlmaLinux:8 | mozjs52 | before 52.9.0-2.el8.alma | 52.9.0-2.el8.alma |
| AlmaLinux:8 | mozjs52 | before 52.9.0-2.el8 | 52.9.0-2.el8 |
| AlmaLinux:8 | mozjs52-devel | before 52.9.0-2.el8 | 52.9.0-2.el8 |
| AlmaLinux:8 | mozjs52-devel | before 52.9.0-2.el8.alma | 52.9.0-2.el8.alma |
| AlmaLinux:8 | mozjs60 | before 60.9.0-4.el8.alma | 60.9.0-4.el8.alma |
| AlmaLinux:8 | mozjs60 | before 60.9.0-4.el8 | 60.9.0-4.el8 |
| AlmaLinux:8 | mozjs60-devel | before 60.9.0-4.el8 | 60.9.0-4.el8 |
| AlmaLinux:8 | mozjs60-devel | before 60.9.0-4.el8.alma | 60.9.0-4.el8.alma |
| AlmaLinux:8 | vala | before 0.40.19-1.el8 | 0.40.19-1.el8 |
| AlmaLinux:8 | vala-devel | before 0.40.19-1.el8 | 0.40.19-1.el8 |
| Debian:12 | gdm3 | before 3.30.2-3 | 3.30.2-3 |
| openSUSE:Tumbleweed | gdm | before 3.38.2-2.7 | 3.38.2-2.7 |
| Red Hat:enterprise_linux:8::appstream | accountsservice | before 0:0.6.50-8.el8 | 0:0.6.50-8.el8 |
| Red Hat:enterprise_linux:8::appstream | accountsservice-debuginfo | before 0:0.6.50-8.el8 | 0:0.6.50-8.el8 |
| Red Hat:enterprise_linux:8::appstream | accountsservice-debugsource | before 0:0.6.50-8.el8 | 0:0.6.50-8.el8 |
+96
Same product
gnome: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-14424The daemon in GDM through 3.29.1 does not properly unexport display objects from its D-Bus interface when they are destroyed, which allows a31Monitor
- CVE-2015-7496GNOME Display Manager (gdm) before 3.18.2 allows physically proximate attackers to bypass the lock screen by holding the Escape key.28Monitor
- CVE-2020-16125gdm3 would start gnome-initial-setup if it cannot contact accountservice27Monitor
- CVE-2013-4169GNOME Display Manager (gdm) before 2.21.1 allows local users to change permissions of arbitrary directories via a symlink attack on /tmp/.X127Monitor
- CVE-2020-27837A flaw was found in GDM in versions prior to 3.38.2.1.25Monitor
- CVE-2017-12164A flaw was discovered in gdm 3.24.1 where gdm greeter was no longer setting the ran_once boolean during autologin.25Monitor
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 |
|---|---|---|
| almalinux:accountsservice-devel | 0.6.50-8.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:baobab | 3.28.0-4.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:clutter | 1.26.2-8.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:clutter-devel | 1.26.2-8.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:clutter-doc | 1.26.2-8.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gjs-devel | 1.56.2-4.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gnome-menus | 3.13.3-11.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gnome-menus-devel | 3.13.3-11.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:gnome-tweaks | 3.28.1-7.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mozjs52 | 52.9.0-2.el8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mozjs52-devel | 52.9.0-2.el8.alma · AlmaLinux:8 | Package registry (OSV) |
| almalinux:mozjs60 | 60.9.0-4.el8.alma · AlmaLinux:8 | Package registry (OSV) |
| debian:gdm3 | 3.30.2-3 · Debian:12 | Package registry (OSV) |
| opensuse:gdm | 3.38.2-2.7 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:accountsservice | 0:0.6.50-8.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:accountsservice-debuginfo | 0:0.6.50-8.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:accountsservice-debugsource | 0:0.6.50-8.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:accountsservice-libs | 0:0.6.50-8.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:accountsservice-libs-debuginfo | 0:0.6.50-8.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:appstream-data | 0:8-20191129.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:baobab | 0:3.28.0-4.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:baobab-debuginfo | 0:3.28.0-4.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:LibRaw | 0:0.19.5-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:LibRaw-debuginfo | 0:0.19.5-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:LibRaw-debugsource | 0:0.19.5-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:LibRaw-samples-debuginfo | 0:0.19.5-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| rocky linux:baobab | 0:3.28.0-4.el8 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:clutter | 0:1.26.2-8.el8 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:gnome-menus | 0:3.13.3-11.el8 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:gnome-tweaks | 0:3.28.1-7.el8 · Rocky Linux:8 | Package registry (OSV) |
+3
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.
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 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.
No nightly-computed relations.
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
- Physical access to the device is required.
- 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
- Physical
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-287 · Improper AuthenticationCVSS vector
CVSS:3.0/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Root cause
Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.
The bug in code
The whole CWE-287 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);Fixed
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);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)
- Authentication AbuseCAPEC-114Medium
- Authentication BypassCAPEC-115Medium
- Identity SpoofingCAPEC-151likelihood: Medium · Medium
- Fake the Source of DataCAPEC-194Medium
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- Utilizing REST's Trust in the System Resource to Obtain Sensitive DataCAPEC-57likelihood: Medium · Very High
- Session HijackingCAPEC-593likelihood: High · Very High
- Token ImpersonationCAPEC-633Medium
ATT&CK techniques
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.