CVE-2026-27601

MEDIUMNVD 5.95.9
EchelonGraph scoreMEDIUM confidence

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

Score 5.9 from GitHub Security Advisory (severity: HIGH) published 2026-03-03. NVD baseline CVSS 5.9; 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

Also known asEUVD-2026-9341 (ENISA EUVD) · GHSA-qpx9-hpmf-5gmw (GitHub Security Advisories)Source: ENISA EUVD

5.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1.1%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Underscore.js is a utility-belt library for JavaScript. Prior to 1.13.8, the _.flatten and _.isEqual functions use recursion without a depth limit. Under very specific conditions, detailed below, an attacker could exploit this in a Denial of Service (DoS) attack by triggering a stack overflow. Untrusted input must be used to create a recursive datastructure, for example using JSON.parse, with no enforced depth limit. The datastructure thus created must be passed to _.flatten or _.isEqual. In the case of _.flatten, the vulnerability can only be exploited if it is possible for a remote client to prepare a datastructure that consists of arrays at all levels AND if no finite depth limit is passed as the second argument to _.flatten. In the case of _.isEqual, the vulnerability can only be exploited if there exists a code path in which two distinct datastructures that were submitted by the same remote client are compared using _.isEqual. For example, if a client submits data that are stored in a database, and the same client can later submit another datastructure that is then compared to the data that were saved in the database previously, OR if a client submits a single request, but its data are parsed twice, creating two non-identical but equivalent datastructures that are then compared. Exceptions originating from the call to _.flatten or _.isEqual, as a result of a stack overflow, are not being caught. This vulnerability is fixed in 1.13.8.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
27
EG Risk 27/100

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)
Severity59% × 45%
Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.1% × 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 every mission impact level.
Exploitation none (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
1.1%
EPSS %ILE
64th
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 (5.9): severity, escalated by confirmed exploitation. This CVE's 5.9 is its impact severity (EG Severity), not escalated.

EG Severity
5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
1.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). 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 every mission impact level.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 every mission impact level.

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

Exploitation none (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

March 3, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 4, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

Unlimited recursion in _.flatten and _.isEqual, potential for DoS attack · Advisory · jashkenas/underscore · GitHub

Affected: version 1.13.8. Upgrading to 1.13.8 or later completely prevents exploitation.

https://github.com/jashkenas/underscore/security/advisories/GHSA-qpx9-hpmf-5gmw
GitHub commit

commit a6e23ae96474 (jashkenas/underscore)

Fix landed in jashkenas/underscore commit a6e23ae96474 — awaiting tagged release

https://github.com/jashkenas/underscore/commit/a6e23ae9647461ec33ad9f92a2ecfc220eea0a84
GitHub commit

commit 411e222eb0ca (jashkenas/underscore)

Fix landed in jashkenas/underscore commit 411e222eb0ca — awaiting tagged release

https://github.com/jashkenas/underscore/commit/411e222eb0ca5d570cc4f6315c02c05b830ed2b4

Patch Availability(4)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhdh/rhdh-hub-rhel9:17809307402026-06-09redhat
redhatrhdh/rhdh-hub-rhel9:17779032622026-05-05redhat
redhatrhdh/rhdh-hub-rhel9:17767842862026-04-22redhat
npmunderscore @ 1.13.8 (fixes <= 1.13.7)—ghsa

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

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
underscore1.13.2~dfsg-1 ... 1.9.1~dfsg-4 (15 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
underscore1.13.4~dfsg+~1.11.4-3 ... 1.13.8~dfsg+~1.13.0-1 (8 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
underscore1.13.4~dfsg+~1.11.4-3 ... 1.13.8~dfsg+~1.13.0-1 (8 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
underscore1.13.4~dfsg+~1.11.4-3 ... 1.13.7~dfsg+~1.13.0-6 (7 versions)
  • every version up to 1.13.8~dfsg+~1.13.0-1: fixed in 1.13.8~dfsg+~1.13.0-1
—
npm(1)
PackageVulnerable rangeFix by version rangeDependents
underscore—
  • every version up to 1.13.8: fixed in 1.13.8
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 41× 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 97 of 242 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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 145 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  2. 2026-11-01 07:56 UTCGHSA enrichmentGHSA-qpx9-hpmf-5gmw · GitHub severity HIGH · GitHub CVSS 5.9
  3. 2026-11-01 07:56 UTCEG score recompute
  4. 2026-10-31 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  5. 2026-10-31 00:25 UTCOSV refresh
  6. 2026-10-30 16:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  7. 2026-10-29 16:33 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  8. 2026-10-28 16:32 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  9. 2026-10-27 16:31 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  10. 2026-10-26 16:31 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  11. 2026-10-25 16:32 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  12. 2026-10-25 14:38 UTCEG score recompute
  13. 2026-10-24 16:32 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  14. 2026-10-23 16:31 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  15. 2026-10-23 04:24 UTCEG score recompute
  16. 2026-10-23 04:24 UTCVendor advisory
  17. 2026-10-22 16:34 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  18. 2026-10-21 16:32 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  19. 2026-10-20 16:32 UTCEPSS rescoreEPSS 1.0% · 63rd percentile
  20. 2026-10-19 16:31 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  21. 2026-10-18 16:31 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  22. 2026-10-18 03:51 UTCEG score recompute
  23. 2026-10-17 16:33 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  24. 2026-10-16 16:41 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  25. 2026-10-15 16:31 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
Show 72 more
  1. 2026-10-14 16:32 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  2. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  3. 2026-10-12 16:33 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  4. 2026-10-12 16:17 UTCEG score recompute
  5. 2026-10-11 19:59 UTCEG score recompute
  6. 2026-10-11 17:13 UTCEG score recompute
  7. 2026-10-11 14:44 UTCEG score recompute
  8. 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  11. 2026-10-08 17:11 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  12. 2026-10-08 13:05 UTCOSV refresh
  13. 2026-10-07 23:47 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  14. 2026-10-06 15:17 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  15. 2026-10-05 17:42 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  16. 2026-10-04 23:21 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  17. 2026-10-03 14:25 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  18. 2026-10-01 19:49 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  20. 2026-09-28 13:51 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  21. 2026-09-26 15:58 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  22. 2026-09-26 00:26 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  23. 2026-09-20 20:15 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  24. 2026-09-18 19:27 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  25. 2026-09-18 18:50 UTCOSV refresh
  26. 2026-09-17 19:30 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  27. 2026-09-16 14:08 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  28. 2026-09-16 05:15 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  29. 2026-09-13 16:47 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  30. 2026-09-12 15:01 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  31. 2026-09-11 14:52 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  32. 2026-09-10 09:34 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  33. 2026-09-08 22:00 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  34. 2026-09-07 16:01 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  35. 2026-09-06 13:47 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  36. 2026-09-04 05:06 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  37. 2026-09-02 14:11 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  38. 2026-09-01 13:53 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  39. 2026-09-01 04:39 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  40. 2026-08-30 22:04 UTCOSV refresh
  41. 2026-08-30 19:17 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  42. 2026-08-30 01:22 UTCEPSS rescoreEPSS 1.0% · 58th percentile
  43. 2026-08-28 21:41 UTCEPSS rescoreEPSS 1.0% · 58th percentile
  44. 2026-08-27 14:25 UTCEPSS rescoreEPSS 1.0% · 58th percentile
  45. 2026-08-26 14:46 UTCEPSS rescoreEPSS 1.0% · 58th percentile
  46. 2026-08-25 13:48 UTCEPSS rescoreEPSS 1.0% · 58th percentile
  47. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  48. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  49. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  50. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  51. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  52. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  53. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  54. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  55. 2026-08-14 08:38 UTCEG score recompute
  56. 2026-08-14 08:38 UTCVendor advisory
  57. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  58. 2026-08-13 00:28 UTCEG score recompute
  59. 2026-08-13 00:28 UTCVendor advisory
  60. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  61. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  62. 2026-08-11 07:56 UTCEG score recompute
  63. 2026-08-11 07:56 UTCVendor advisory
  64. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  65. 2026-08-10 08:09 UTCEG score recompute
  66. 2026-08-10 08:09 UTCVendor advisory
  67. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  68. 2026-08-09 08:16 UTCEG score recompute
  69. 2026-08-09 08:16 UTCVendor advisory
  70. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  71. 2026-08-07 20:10 UTCEG score recompute
  72. 2026-08-07 20:10 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-27601?
CVE-2026-27601 is a medium-severity vulnerability; its CVE record was published on March 3, 2026. Underscore.js is a utility-belt library for JavaScript. Prior to 1.13.8, the _.flatten and _.isEqual functions use recursion without a depth limit. Under very specific conditions, detailed below, an attacker could exploit this in a Denial of Service (DoS) attack by triggering a stack overflow.…
When was the CVE record for CVE-2026-27601 published?
The CVE record for CVE-2026-27601 was published on March 3, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-27601 actively exploited?
CVE-2026-27601 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.1% probability of exploitation in the next 30 days (64th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-27601?
CVE-2026-27601 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-27601?
A fix for CVE-2026-27601 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-27601 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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