CVE-2026-48990

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (17th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
5.3EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (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: 0.3%CVSS: 5.3Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions 1.3.4 through 1.6.5, joserfc accepts oversized RFC7797 b64=false JWS payloads without applying JWSRegistry.max_payload_length, which can lead to resource exhaustion. The normal JWS compact and flattened JSON paths reject payloads above the configured payload-size limit with ExceededSizeError. The RFC7797 unencoded payload paths do not make the same check. A valid b64=false compact or flattened JSON JWS can therefore deserialize successfully with a payload larger than JWSRegistry.max_payload_length. Applications that accept lower-trust JWS values and rely on joserfc to reject oversized token content during verification have a moderate availability risk. This issue has been fixed in version 1.6.7.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
55
EG Risk 55/100

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)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 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.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
17th
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 (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). 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; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

June 17, 2026

Last Modified

June 23, 2026

Advisory Details (2)

Auto-updated Jun 17, 2026
Patch available. Sources: github_release, github.
GitHub advisoryMentions a patch (unverified)

RFC7797 b64=false JWS payloads bypass JWSRegistry payload-size limits during deserialization · Advisory · authlib/joserfc · GitHub

https://github.com/authlib/joserfc/security/advisories/GHSA-wphv-vfrh-23q5
GitHub release Patch Available

1.6.7

Patch available: authlib/joserfc 1.6.7

https://github.com/authlib/joserfc/releases/tag/1.6.7

Patch Availability(4)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatansible-automation-platform-26/lightspeed-chatbot-rhel9:17856461882026-08-04redhat
redhatansible-automation-platform-27/lightspeed-chatbot-rhel9:17854267342026-08-04redhat
redhatmta/mta-solution-server-rhel9:17841098832026-07-21redhat
redhatjaeger-main-2.19.0-1.hum12026-06-10redhat

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:13(1)
PackageVulnerable rangeFix by version rangeDependents
joserfc1.1.0-1 ... 1.7.4-1 (22 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
joserfc1.1.0-1 ... 1.6.5-1 (16 versions)
  • every version up to 1.6.8-1: fixed in 1.6.8-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
joserfc1.3.4 ... 1.6.5 (13 versions)
  • 1.3.4 up to 1.6.7: fixed in 1.6.7
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 33× 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 198 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 98 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  2. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  3. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  4. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  5. 2026-10-18 03:34 UTCEG score recompute
  6. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  7. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  8. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  9. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  10. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  11. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  12. 2026-10-12 16:00 UTCVendor advisory
  13. 2026-10-12 16:00 UTCEG score recompute
  14. 2026-10-11 19:43 UTCEG score recompute
  15. 2026-10-11 16:57 UTCEG score recompute
  16. 2026-10-11 14:22 UTCEG score recompute
  17. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  18. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  19. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  20. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  21. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  22. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  23. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  24. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  25. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 16th percentile
Show 75 more
  1. 2026-10-02 16:40 UTCOSV refresh
  2. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  4. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  5. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  6. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  7. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  8. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  10. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  11. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  12. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  13. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  14. 2026-09-13 14:07 UTCEG score recompute
  15. 2026-09-13 14:07 UTCVendor advisory
  16. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  17. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  18. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  20. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  21. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  22. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  23. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  24. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  25. 2026-08-30 21:14 UTCEG score recompute
  26. 2026-08-30 21:14 UTCVendor advisory
  27. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  28. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  29. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  30. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  31. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  32. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  33. 2026-08-24 06:49 UTCVendor advisory
  34. 2026-08-23 03:52 UTCEG score recompute
  35. 2026-08-23 03:52 UTCVendor advisory
  36. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  37. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  38. 2026-08-21 11:54 UTCEG score recompute
  39. 2026-08-21 11:54 UTCVendor advisory
  40. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  41. 2026-08-20 09:38 UTCEG score recompute
  42. 2026-08-20 09:38 UTCVendor advisory
  43. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  44. 2026-08-19 08:05 UTCEG score recompute
  45. 2026-08-19 08:05 UTCVendor advisory
  46. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  47. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  48. 2026-08-17 12:29 UTCEG score recompute
  49. 2026-08-17 12:29 UTCVendor advisory
  50. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  51. 2026-08-16 10:41 UTCEG score recompute
  52. 2026-08-16 10:41 UTCVendor advisory
  53. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  54. 2026-08-15 09:08 UTCEG score recompute
  55. 2026-08-15 09:08 UTCVendor advisory
  56. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  57. 2026-08-14 06:38 UTCEG score recompute
  58. 2026-08-14 06:38 UTCVendor advisory
  59. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  60. 2026-08-13 05:04 UTCEG score recompute
  61. 2026-08-13 05:04 UTCVendor advisory
  62. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  63. 2026-08-12 03:31 UTCEG score recompute
  64. 2026-08-12 03:31 UTCVendor advisory
  65. 2026-08-11 01:58 UTCEG score recompute
  66. 2026-08-11 01:58 UTCVendor advisory
  67. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  68. 2026-08-10 00:25 UTCEG score recompute
  69. 2026-08-10 00:25 UTCVendor advisory
  70. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  71. 2026-08-08 22:52 UTCEG score recompute
  72. 2026-08-08 22:52 UTCVendor advisory
  73. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  74. 2026-08-07 21:17 UTCEG score recompute
  75. 2026-08-07 21:17 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-48990?
CVE-2026-48990 is a medium-severity vulnerability; its CVE record was published on June 17, 2026. joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions 1.3.4 through 1.6.5, joserfc accepts oversized RFC7797 b64=false JWS payloads without applying JWSRegistry.maxpayloadlength, which can lead to resource exhaustion.…
When was the CVE record for CVE-2026-48990 published?
The CVE record for CVE-2026-48990 was published on June 17, 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 23, 2026; the record at its source may have been updated since.
Is CVE-2026-48990 actively exploited?
CVE-2026-48990 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (17th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-48990?
CVE-2026-48990 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-48990?
A fix for CVE-2026-48990 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-48990 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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