CVE-2018-6954

HIGHNVD 7.87.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-13. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 7.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

systemd-tmpfiles in systemd through 237 mishandles symlinks present in non-terminal path components, which allows local users to obtain ownership of arbitrary files via vectors involving creation of a directory and a file under that directory, and later replacing that directory with a symlink. This occurs even if the fs.protected_symlinks sysctl is turned on.

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
35
EG Risk 35/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity78% × 45%
Impact severity (EG Severity): CVSS 7.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
43rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.

EG Severity
7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-21). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

February 13, 2018

Last Modified

June 9, 2025

Advisory Details (3)

Auto-updated Oct 21, 2026
Patch available.
Web page

Pony Mail

https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
Web page

Pony Mail

https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
Web page

tmpfiles: symlinks are followed in non-terminal path components (CVE-2018-6954) · Issue #7986 · systemd/systemd · GitHub

https://github.com/systemd/systemd/issues/7986

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntuudev-udeb (229-4ubuntu21.8) @ xenial2026-10-21ubuntu
ubuntuudev-udeb (229-4ubuntu21.9) @ xenial2026-10-21ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 238-1: fixed in 238-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 238-1: fixed in 238-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 238-1: fixed in 238-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 238-1: fixed in 238-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 11× in last 7d / 36× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 95 of 185 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 5 repeat rows among the latest 100 are merged into the row they repeat. The 90 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  2. 2026-10-22 16:28 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  3. 2026-10-21 19:32 UTCEG score recompute
  4. 2026-10-21 19:32 UTCVendor advisory
  5. 2026-10-21 19:32 UTCGHSA enrichmentGHSA-fgm4-rh7c-g9fg · GitHub severity HIGH · GitHub CVSS 7.8
  6. 2026-10-21 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  7. 2026-10-20 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  8. 2026-10-19 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  9. 2026-10-18 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  10. 2026-10-18 10:02 UTCEG score recompute
  11. 2026-10-17 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-10-16 16:30 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-10-15 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-10-14 16:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  15. 2026-10-13 16:27 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-10-12 20:08 UTCEG score recompute
  17. 2026-10-12 16:28 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  18. 2026-10-12 00:32 UTCEG score recompute
  19. 2026-10-11 13:41 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  20. 2026-10-10 19:55 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  21. 2026-10-09 20:03 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-10-08 16:37 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
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  25. 2026-10-05 17:39 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
Show 70 more
  1. 2026-10-04 23:18 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  2. 2026-10-03 14:21 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  3. 2026-10-01 19:44 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  4. 2026-09-30 14:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  5. 2026-09-30 10:04 UTCEG score recompute
  6. 2026-09-29 15:12 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-09-29 09:52 UTCOSV refresh
  8. 2026-09-28 13:46 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  9. 2026-09-27 13:40 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-09-26 15:53 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-09-24 13:59 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  12. 2026-09-23 13:42 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-09-21 20:27 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-09-20 20:10 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  15. 2026-09-19 15:36 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  16. 2026-09-18 19:22 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  17. 2026-09-17 19:22 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  18. 2026-09-15 03:05 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  19. 2026-09-13 16:42 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  20. 2026-09-11 14:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  21. 2026-09-11 09:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-09-09 18:23 UTCOSV refresh
  23. 2026-09-06 13:44 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  24. 2026-09-04 13:56 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  25. 2026-09-04 05:02 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  26. 2026-09-02 14:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  27. 2026-09-01 03:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  28. 2026-08-30 19:13 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  29. 2026-08-30 01:18 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  30. 2026-08-28 21:36 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  31. 2026-08-27 14:21 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
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  34. 2026-08-24 14:11 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  35. 2026-08-22 23:07 UTCOSV refresh
  36. 2026-08-21 23:45 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  37. 2026-08-20 22:51 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  38. 2026-08-19 17:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  39. 2026-08-18 13:44 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  40. 2026-08-17 13:43 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  41. 2026-08-16 14:52 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  42. 2026-08-16 02:10 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  43. 2026-08-15 01:26 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  44. 2026-08-13 21:56 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  45. 2026-08-12 13:47 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  46. 2026-08-09 13:43 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  47. 2026-08-08 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  48. 2026-08-07 16:23 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  49. 2026-08-07 01:56 UTCOSV refresh
  50. 2026-08-06 13:42 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  51. 2026-08-04 15:05 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  52. 2026-08-04 10:33 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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  54. 2026-08-02 02:23 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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  56. 2026-07-30 16:24 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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  58. 2026-07-28 15:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  59. 2026-07-27 14:05 UTCEPSS rescoreEPSS 0.5% · 41st percentile
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  63. 2026-07-23 14:15 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  64. 2026-07-23 01:37 UTCEG score recompute
  65. 2026-07-22 22:17 UTCEG score recompute
  66. 2026-07-22 14:05 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  67. 2026-07-21 17:48 UTCOSV refresh
  68. 2026-07-21 15:22 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  69. 2026-07-20 17:04 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  70. 2026-07-19 14:28 UTCEPSS rescoreEPSS 0.5% · 41st percentile

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Frequently asked(5)

What is CVE-2018-6954?
CVE-2018-6954 is a high-severity vulnerability; its CVE record was published on February 13, 2018. systemd-tmpfiles in systemd through 237 mishandles symlinks present in non-terminal path components, which allows local users to obtain ownership of arbitrary files via vectors involving creation of a directory and a file under that directory, and later replacing that directory with a symlink. This…
When was CVE-2018-6954 made public?
CVE-2018-6954 was made public on February 13, 2018: that is the date its CVE record's CNA, MITRE Corporation, gives for when the vulnerability was made public. The CVE record itself was published on February 13, 2018. EchelonGraph's copy of the record carries a last-modified date of June 9, 2025; the record at its source may have been updated since.
Is CVE-2018-6954 actively exploited?
CVE-2018-6954 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (43rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2018-6954?
CVE-2018-6954 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2018-6954?
A fix for CVE-2018-6954 is available: update to the fixed version the vendor names in its advisory.

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