CVE-2026-40253

MEDIUMNVD 6.86.8
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 6.8 under NVD CVSS v3. EPSS exploit probability: 0.2% (5th 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-2026-23318 (ENISA EUVD)Source: ENISA EUVD

6.8EG
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: 6.8Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

openCryptoki is a PKCS#11 library and provides tooling for Linux and AIX. In versions 3.26.0 and below, the BER/DER decoding functions in the shared common library (asn1.c) accept a raw pointer but no buffer length parameter, and trust attacker-controlled BER length fields without validating them against actual buffer boundaries. All primitive decoders are affected: ber_decode_INTEGER, ber_decode_SEQUENCE, ber_decode_OCTET_STRING, ber_decode_BIT_STRING, and ber_decode_CHOICE. Additionally, ber_decode_INTEGER can produce integer underflows when the encoded length is zero. An attacker supplying a malformed BER-encoded cryptographic object through PKCS#11 operations such as C_CreateObject or C_UnwrapKey, token loading from disk, or remote backend communication can trigger out-of-bounds reads. This affects all token backends (Soft, ICA, CCA, TPM, EP11, ICSF) since the vulnerable code is in the shared common library. A patch is available thorugh commit ed378f463ef73364c89feb0fc923f4dc867332a3.

CVSS v3
6.8
EG Score
6.8MEDIUMmedium confidence
EG Risk
47
EG Risk 47/100

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)
Severity68% × 45%
Impact severity (EG Severity): CVSS 6.8 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 (6.8): severity, escalated by confirmed exploitation. This CVE's 6.8 is its impact severity (EG Severity), not escalated.

EG Severity
6.8 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 (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: 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.

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 16, 2026

Last Modified

April 22, 2026

Advisory Details (2)

Auto-updated Jun 14, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

Memory safety vulnerabilities in BER/DER decoders in asn1.c · Advisory · opencryptoki/opencryptoki · GitHub

https://github.com/opencryptoki/opencryptoki/security/advisories/GHSA-c9cf-6vr4-wfxm
GitHub commit Patch Available

commit ed378f463ef7 (opencryptoki/opencryptoki)

Patch available: opencryptoki/opencryptoki v3.27.0 (contains commit ed378f463ef7)

https://github.com/opencryptoki/opencryptoki/commit/ed378f463ef73364c89feb0fc923f4dc867332a3

Vendor Advisories for CVE-2026-40253(6)

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

Patch Availability(6)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatopencryptoki-0:3.24.0-5.el9_6.22026-07-08redhat
redhatopencryptoki-0:3.24.0-6.el10_0.22026-07-08redhat
redhatopencryptoki-0:3.22.0-3.el9_4.32026-06-30redhat
redhatopencryptoki-0:3.26.0-2.el9_8.22026-06-23redhat
redhatopencryptoki-0:3.26.0-3.el10_2.12026-06-23redhat
redhatopencryptoki-0:3.22.0-3.el8_10.32026-06-16redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
opencryptoki3.23.0+dfsg-0.1 ... 3.8.1+dfsg-3.2 (6 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
opencryptoki3.23.0+dfsg-0.1 ... 3.8.1+dfsg-3.2 (6 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
opencryptoki3.23.0+dfsg-0.3
  • every version up to 3.23.0+dfsg-0.3+deb13u1: fixed in 3.23.0+dfsg-0.3+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
opencryptoki3.23.0+dfsg-0.3, 3.23.0+dfsg-0.4
  • every version up to 3.27.0-1: fixed in 3.27.0-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 38× 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 99 of 205 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 106 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

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

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-40253?
CVE-2026-40253 is a medium-severity vulnerability; its CVE record was published on April 16, 2026. openCryptoki is a PKCS#11 library and provides tooling for Linux and AIX. In versions 3.26.0 and below, the BER/DER decoding functions in the shared common library (asn1.c) accept a raw pointer but no buffer length parameter, and trust attacker-controlled BER length fields without validating them…
When was the CVE record for CVE-2026-40253 published?
The CVE record for CVE-2026-40253 was published on April 16, 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 April 22, 2026; the record at its source may have been updated since.
Is CVE-2026-40253 actively exploited?
CVE-2026-40253 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-2026-40253?
CVE-2026-40253 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2026-40253?
A fix for CVE-2026-40253 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-40253 are linked in the Vendor Advisories panel on this page.

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