CVE-2026-77159

MEDIUMPre-NVD 5.55.5
EchelonGraph scoreMEDIUM confidence

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

Score 5.5 from GitHub Security Advisory published 2026-09-11. A secondary CVSS source baseline 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Elevated

Also known asEUVD-2026-76034 (ENISA EUVD) · GHSA-wmhq-5pq5-8474 (GitHub Security Advisories)Source: ENISA EUVD

5.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

A symlink-following flaw was found in libvirt's qemuTPMEmulatorPrepareHost() function. The function uses a path-based chown() on the swtpm logfile without checking for symbolic links. A local attacker with access to the swtpm account can replace the logfile with a symlink, causing libvirtd (running as root) to transfer ownership of an arbitrary file to the swtpm user.

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
41
EG Risk 41/100

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)
Severity55% × 45%
Impact severity (EG Severity): CVSS 5.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
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 public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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
0.2%
EPSS %ILE
5th
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 (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.

EG Severity
5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: 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 public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (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

September 11, 2026

Last Modified

September 16, 2026

Advisory Details (3)

Auto-updated Sep 11, 2026
Patch available. Sources: redhat.
Web page

Unsafe chown in qemuTPMEmulatorPrepareHost() allows arbitrary file ownership transfer via symlink (#909) · Issues · libvirt / libvirt · GitLab

https://gitlab.com/libvirt/libvirt/-/work_items/909
Red Hat

2531811 – (CVE-2026-77159) CVE-2026-77159 libvirt: Unsafe chown in qemuTPMEmulatorPrepareHost() allows arbitrary file ownership change via symlink

https://bugzilla.redhat.com/show_bug.cgi?id=2531811
Red HatMentions a patch (unverified)

CVE-2026-77159 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-77159

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibvirt0 (12.0.0-1ubuntu5.5) @ resolute2026-10-22ubuntu
ubuntulibvirt0-hwe (12.0.0-1ubuntu5.5) @ resolute2026-10-22ubuntu

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

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
libvirt10.0.0-1 ... 9.9.0-1 (71 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
libvirt11.10.0-1 ... 12.7.0-1 (22 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libvirt11.10.0-1 ... 12.6.0-1 (18 versions)
  • every version up to 12.7.0-1: fixed in 12.7.0-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 62× 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 100 of 140 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. None are among the latest 100 rows. The 40 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  4. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  5. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  6. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  7. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-10-25 14:01 UTCEG score recompute
  10. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  11. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  12. 2026-10-22 18:23 UTCEG score recompute
  13. 2026-10-22 18:23 UTCVendor advisory
  14. 2026-10-22 18:23 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  15. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  16. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  17. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  18. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  20. 2026-10-18 03:12 UTCEG score recompute
  21. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  22. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  23. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  24. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  25. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.2% · 4th percentile
Show 75 more
  1. 2026-10-12 15:37 UTCEG score recompute
  2. 2026-10-11 21:41 UTCVendor advisory
  3. 2026-10-11 21:41 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  4. 2026-10-11 19:23 UTCEG score recompute
  5. 2026-10-11 16:39 UTCEG score recompute
  6. 2026-10-11 13:58 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  9. 2026-10-10 19:38 UTCEG score recompute
  10. 2026-10-10 19:38 UTCVendor advisory
  11. 2026-10-10 19:38 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  13. 2026-10-09 19:33 UTCEG score recompute
  14. 2026-10-09 19:33 UTCVendor advisory
  15. 2026-10-09 19:33 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  16. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  17. 2026-10-08 09:59 UTCEG score recompute
  18. 2026-10-08 09:59 UTCVendor advisory
  19. 2026-10-08 09:59 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  20. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  21. 2026-10-07 10:28 UTCEG score recompute
  22. 2026-10-07 10:28 UTCVendor advisory
  23. 2026-10-07 10:27 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  24. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  25. 2026-10-06 10:57 UTCEG score recompute
  26. 2026-10-06 10:57 UTCVendor advisory
  27. 2026-10-06 10:57 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  28. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  29. 2026-10-05 11:26 UTCEG score recompute
  30. 2026-10-05 11:26 UTCVendor advisory
  31. 2026-10-05 11:26 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  32. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  33. 2026-10-04 11:56 UTCVendor advisory
  34. 2026-10-04 11:55 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  35. 2026-10-03 12:25 UTCEG score recompute
  36. 2026-10-03 12:25 UTCVendor advisory
  37. 2026-10-03 12:24 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  38. 2026-10-02 12:54 UTCEG score recompute
  39. 2026-10-02 12:54 UTCVendor advisory
  40. 2026-10-02 12:54 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  41. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  42. 2026-10-01 13:24 UTCEG score recompute
  43. 2026-10-01 13:24 UTCVendor advisory
  44. 2026-10-01 13:24 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  45. 2026-09-30 13:54 UTCEG score recompute
  46. 2026-09-30 13:54 UTCVendor advisory
  47. 2026-09-30 13:54 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  48. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  49. 2026-09-29 13:49 UTCEG score recompute
  50. 2026-09-29 13:49 UTCVendor advisory
  51. 2026-09-29 13:49 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  52. 2026-09-28 14:18 UTCEG score recompute
  53. 2026-09-28 14:18 UTCVendor advisory
  54. 2026-09-28 14:18 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  55. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  56. 2026-09-27 14:47 UTCEG score recompute
  57. 2026-09-27 14:47 UTCVendor advisory
  58. 2026-09-27 14:47 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  59. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  60. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  61. 2026-09-26 15:17 UTCEG score recompute
  62. 2026-09-26 15:17 UTCVendor advisory
  63. 2026-09-26 15:17 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  64. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  65. 2026-09-25 15:47 UTCVendor advisory
  66. 2026-09-25 15:47 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  67. 2026-09-24 16:17 UTCEG score recompute
  68. 2026-09-24 16:17 UTCVendor advisory
  69. 2026-09-24 16:17 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  70. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  71. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  72. 2026-09-23 16:47 UTCVendor advisory
  73. 2026-09-23 16:47 UTCGHSA enrichmentGHSA-wmhq-5pq5-8474 · GitHub CVSS 5.5
  74. 2026-09-22 17:16 UTCEG score recompute
  75. 2026-09-22 17:16 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-77159?
CVE-2026-77159 is a medium-severity vulnerability; its CVE record was published on September 11, 2026. A symlink-following flaw was found in libvirt's qemuTPMEmulatorPrepareHost() function. The function uses a path-based chown() on the swtpm logfile without checking for symbolic links. A local attacker with access to the swtpm account can replace the logfile with a symlink, causing libvirtd (running…
When was CVE-2026-77159 made public?
CVE-2026-77159 was made public on September 11, 2026: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on September 11, 2026. EchelonGraph's copy of the record carries a last-modified date of September 16, 2026; the record at its source may have been updated since.
Is CVE-2026-77159 actively exploited?
CVE-2026-77159 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (5th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77159?
CVE-2026-77159 has a CVSS base score of 5.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77159?
A fix for CVE-2026-77159 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77159 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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