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NVD / CVE Program· CNA canonical

CVE-2018-15687: systemd: chown_one() can dereference symlinks

Noroxi assessment

Priority: Monitor (action score 28/100)

  • Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1% (FIRST EPSS); higher than 64.2% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: systemd (Debian:12) 239-11; systemd (openSUSE:Tumbleweed) 249.4-2.2.

Low priority for now. Upgrade to systemd (Debian:12) 239-11; systemd (openSUSE:Tumbleweed) 249.4-2.2 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

A race condition in chown_one() of systemd allows an attacker to cause systemd to set arbitrary permissions on arbitrary files. Affected releases are systemd versions up to and including 239.

HighCVSS 7.0 · v3.1—Proof of concept Fix available
Published
Oct 26, 2018
Updated
Jun 16, 2026
EPSS
1.0% · 64th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.0%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.0
CNA · canonical
7.8
0.8 point gap

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2018-15687

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
canonicalubuntu linux
systemd projectsystemd

Affected versions

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

  • canonical ubuntu linux16.04
  • canonical ubuntu linux18.04
  • canonical ubuntu linux18.10
  • systemd project systemd235 and later · before 240

Versions reported by the vendor

Affected version ranges reported by the assigning authority (canonical). Independent of NVD's CPE analysis and usually ahead of it.

  • systemd systemd

    • unspecified and later · up to and including 239affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12systemdbefore 239-11239-11
openSUSE:Tumbleweedsystemdbefore 249.4-2.2249.4-2.2

Same product

canonical: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-3493The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities KEV
    76This week
  • CVE-2017-14492Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via
    67This week
  • CVE-2017-14493Stack-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code vi
    65This week

Published before and after this one in the same product

  • ← EarlierCVE-2018-18653Oct 25, 2018 · The Linux kernel, as used in Ubuntu 18.10 and when booted with UEFI Secure Boot enabled, allows privileged local users to bypass intended Se
    31Monitor
  • ← EarlierCVE-2018-15686Oct 26, 2018 · systemd: reexec state injection: fgets() on overlong lines leads to line splitting
    32Monitor
  • Later →CVE-2018-5407Nov 15, 2018 · Simultaneous Multi-threading (SMT) in processors can enable local users to exploit software vulnerable to timing attacks via a side-channel
    19Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
debian:systemd239-11 · Debian:12Package registry (OSV)
opensuse:systemd249.4-2.2 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrylocal2018-10-29

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.

  1. Published
  2. First PoC+3 d
  3. TodayOct 27, 2026+2923 d
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.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • 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
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

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

All records