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CVE-2017-8900· NVD / CVE Program· CNA mitre

LightDM through 1.22.0, when systemd is used in Ubuntu 16.10 and 17.x, allows physically proximate attackers to bypass intended AppArmor res

LightDM through 1.22.0, when systemd is used in Ubuntu 16.10 and 17.x, allows physically proximate attackers to bypass intended AppArmor restrictions and visit the home directories of arbitrary users by establishing a guest session.

MediumCVSS 4.6 · v3.0—No exploit No fix recorded
Published
May 12, 2017
Updated
Jun 16, 2026
EPSS
0.4% · 34th percentile
CWE
—
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Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

Affected systems

VendorProduct
lightdm projectlightdm
canonicalubuntu linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • lightdm project lightdmup to 1.22.0 inclusive

Same product

lightdm project: all records

Other highest-scoring records for the same primary product.

  • CVE-2011-3349lightdm before 0.9.6 writes in .dmrc and Xauthority files using root permissions while the files are in user controlled folders.
    31Monitor
  • CVE-2017-7358In LightDM through 1.22.0, a directory traversal issue in debian/guest-account.sh allows local attackers to own arbitrary directory path loc
    30Monitor
  • CVE-2015-8316Array index error in LightDM (aka Light Display Manager) 1.14.3, 1.16.x before 1.16.6 when the XDMCP server is enabled allows remote attacke
    24Monitor

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

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.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Physical
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

—

CVSS vector

CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

nvd-primary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

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 help

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

All records