CVE-2026-39956

MEDIUMNVD 6.16.1
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.2% (7th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Elevated

Also known asEUVD-2026-22126 (ENISA EUVD)Source: ENISA EUVD

6.1EG
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: 6.1Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

jq is a command-line JSON processor. Prior to version 1.8.2, the _strindices builtin in jq's src/builtin.c passes its arguments directly to jv_string_indexes() without verifying they are strings, and jv_string_indexes() in src/jv.c relies solely on assert() checks that are stripped in release builds compiled with -DNDEBUG. This allows an attacker to crash jq trivially with input like _strindices(0), and by crafting a numeric value whose IEEE-754 bit pattern maps to a chosen pointer, achieve a controlled pointer dereference and limited memory read/probe primitive. Any deployment that evaluates untrusted jq filters against a release build is vulnerable. This issue has been patched in commit fdf8ef0f0810e3d365cdd5160de43db46f57ed03, which is part of version 1.8.2.

CVSS v3
6.1
EG Score
6.1MEDIUMmedium confidence
EG Risk
43
EG Risk 43/100

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)
Severity61% × 45%
Impact severity (EG Severity): CVSS 6.1 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
7th
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 (6.1): severity, escalated by confirmed exploitation. This CVE's 6.1 is its impact severity (EG Severity), not escalated.

EG Severity
6.1 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS. 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

April 13, 2026

Last Modified

October 26, 2026

Advisory Details (2)

Auto-updated Aug 2, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

jq _strindices missing runtime type checks lead to crash and limited memory disclosure · Advisory · jqlang/jq · GitHub

https://github.com/jqlang/jq/security/advisories/GHSA-6gc3-3g9p-xx28
GitHub commit

commit fdf8ef0f0810 (jqlang/jq)

Fix landed in jqlang/jq commit fdf8ef0f0810 — awaiting tagged release

https://github.com/jqlang/jq/commit/fdf8ef0f0810e3d365cdd5160de43db46f57ed03

Vendor Advisories for CVE-2026-39956(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntujq (1.5+dfsg-1ubuntu0.1+esm4) @ xenial2026-06-14ubuntu
ubuntulibjq1 (1.8.1-4ubuntu2) @ resolute2026-06-14ubuntu
redhatjq-main-1.8.1-3.hum12026-04-16redhat

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

(7 across 7 ecosystems)
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
jq—
  • 2026-04-02 up to 1.8.2-r0: fixed in 1.8.2-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
jq—
  • 2026-04-02 up to 1.8.2-r0: fixed in 1.8.2-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
jq—
  • 2026-04-02 up to 1.8.2-r0: fixed in 1.8.2-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
jq1.6-2.1, 1.6-2.1+deb11u1
  • every version up to 1.6-2.1+deb11u2: fixed in 1.6-2.1+deb11u2
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
jq1.6-2.1, 1.6-2.1+deb12u1
  • every version up to 1.6-2.1+deb12u2: fixed in 1.6-2.1+deb12u2
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
jq1.7.1-6+deb13u1
  • every version up to 1.7.1-6+deb13u2: fixed in 1.7.1-6+deb13u2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
jq1.8.0-1, 1.8.1-1, 1.8.1-2, 1.8.1-3, 1.8.1-4
  • every version up to 1.8.1-5: fixed in 1.8.1-5
—

Weakness Classification(3)

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 / 30× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 234 rows on record for this CVE, as 99 entries (1 repeat merged).

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. 1 repeat row among the latest 100 is merged into the row it repeats. The 134 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

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

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Frequently asked(5)

What is CVE-2026-39956?
CVE-2026-39956 is a medium-severity vulnerability; its CVE record was published on April 13, 2026. jq is a command-line JSON processor. Prior to version 1.8.2, the _strindices builtin in jq's src/builtin.c passes its arguments directly to jv_string_indexes() without verifying they are strings, and jv_string_indexes() in src/jv.c relies solely on assert() checks that are stripped in release…
When was the CVE record for CVE-2026-39956 published?
The CVE record for CVE-2026-39956 was published on April 13, 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 October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-39956 actively exploited?
CVE-2026-39956 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (7th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-39956?
CVE-2026-39956 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-39956?
A fix for CVE-2026-39956 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-39956 are linked in the Vendor Advisories panel on this page.

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