CVE-2026-55858

MEDIUMPre-NVD 5.95.9
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.9% (57th 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
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: 0.9%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, the connector encodes and decodes protocol text and performs client-side escaping under the assumption that the connection character set is UTF-8. The server can report a mid-session change to character_set_client through OK-packet session-state tracking, including a change caused by SET NAMES, a stored routine or trigger, server configuration, or a hostile server. If character_set_client changes to a non-UTF-8 value, the driver continues to read and write UTF-8 while the server interprets the same bytes under another encoding, causing silent data corruption and a client/server charset-confusion mismatch that can defeat byte-wise quoting or escaping. The fix accepts only utf8, utf8mb3, or utf8mb4 after initialization; any other value causes SQLException with SQLState 08000 and closes the connection. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9.

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 intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity59% × 45%
The EG Score, 5.9 of 10.
Exploitation0.9% × 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
0.9%
EPSS %ILE
57th
KEV
Not listed

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.

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

August 28, 2026

Last Modified

September 8, 2026

Advisory Details (10)

Auto-updated Aug 28, 2026
Patch available. Sources: github, github_commit, github_release.
Web page

[CONJ-1317] Reject runtime switch of the connection character set to a non-UTF-8 charset - Jira

https://jira.mariadb.org/browse/CONJ-1317
GitHub release Patch Available

MariaDB Connector/Java 3.5.9

Patch available: mariadb-corporation/mariadb-connector-j 3.5.9

https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9
GitHub release Patch Available

MariaDB Connector/Java 3.4.3

Patch available: mariadb-corporation/mariadb-connector-j 3.4.3

https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3
GitHub release Patch Available

MariaDB Connector/Java 3.3.5

Patch available: mariadb-corporation/mariadb-connector-j 3.3.5

https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.5
GitHub release Patch Available

MariaDB Connector/Java 2.7.14

Patch available: mariadb-corporation/mariadb-connector-j 2.7.14

https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/2.7.14
GitHub commit Patch Available

commit c555c9b47752 (mariadb-corporation/mariadb-connector-j)

Patch available: mariadb-corporation/mariadb-connector-j 3.4.3 (contains commit c555c9b47752)

https://github.com/mariadb-corporation/mariadb-connector-j/commit/c555c9b477521be0c35c3a5461f9f46681553607
GitHub commit Patch Available

commit 8cfd9df69737 (mariadb-corporation/mariadb-connector-j)

Patch available: mariadb-corporation/mariadb-connector-j 3.3.5 (contains commit 8cfd9df69737)

https://github.com/mariadb-corporation/mariadb-connector-j/commit/8cfd9df697372ad4ed09fe87a34b34babb6d43d6
GitHub commit Patch Available

commit 7b3c69221b54 (mariadb-corporation/mariadb-connector-j)

Patch available: mariadb-corporation/mariadb-connector-j 3.5.9 (contains commit 7b3c69221b54)

https://github.com/mariadb-corporation/mariadb-connector-j/commit/7b3c69221b5463ee03472654040b3f6b9e5329c7
GitHub commit Patch Available

commit 300716bef1e1 (mariadb-corporation/mariadb-connector-j)

Patch available: mariadb-corporation/mariadb-connector-j 2.7.14 (contains commit 300716bef1e1)

https://github.com/mariadb-corporation/mariadb-connector-j/commit/300716bef1e1d0370a41be7863b88aa2d55fbb69
GitHub advisoryMentions a patch (unverified)

Inappropriate Encoding for Output Context in org.mariadb.jdbc:mariadb-java-client · Advisory · mariadb-corporation/mariadb-connector-j · GitHub

Affected: 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Upgrade to the patched release on your branch (3

https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-xvr9-35cr-46v9

Vendor Advisories for CVE-2026-55858(1)

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

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
org.mariadb.jdbc:mariadb-java-client3.5.0 ... 3.5.8 (9 versions)
  • every version up to 2.7.14: fixed in 2.7.14
  • 3.0.0 up to 3.3.5: fixed in 3.3.5
  • 3.4.0 up to 3.4.3: fixed in 3.4.3
  • 3.5.0 up to 3.5.9: fixed in 3.5.9
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 49× 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.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  3. 2026-10-12 15:55 UTCEG score recompute
  4. 2026-10-11 19:38 UTCEG score recompute
  5. 2026-10-11 16:53 UTCEG score recompute
  6. 2026-10-11 14:16 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  9. 2026-10-10 01:43 UTCEG score recompute
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  11. 2026-10-09 02:36 UTCEG score recompute
  12. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  13. 2026-10-08 00:47 UTCEG score recompute
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  15. 2026-10-06 18:01 UTCEG score recompute
  16. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  17. 2026-10-05 18:54 UTCEG score recompute
  18. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  19. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  20. 2026-10-03 19:18 UTCEG score recompute
  21. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  22. 2026-10-02 18:54 UTCEG score recompute
  23. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  24. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  25. 2026-09-30 19:48 UTCEG score recompute
Show 53 more
  1. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  2. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  3. 2026-09-29 14:10 UTCEG score recompute
  4. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  5. 2026-09-27 14:40 UTCEG score recompute
  6. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  7. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  8. 2026-09-26 15:33 UTCEG score recompute
  9. 2026-09-24 16:47 UTCEG score recompute
  10. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  11. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  12. 2026-09-22 18:17 UTCEG score recompute
  13. 2026-09-21 17:39 UTCEG score recompute
  14. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  15. 2026-09-19 19:22 UTCEG score recompute
  16. 2026-09-18 19:57 UTCEG score recompute
  17. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  18. 2026-09-17 20:50 UTCEG score recompute
  19. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  20. 2026-09-16 18:57 UTCEG score recompute
  21. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  22. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  23. 2026-09-15 18:42 UTCEG score recompute
  24. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  25. 2026-09-13 20:19 UTCEG score recompute
  26. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  27. 2026-09-12 21:12 UTCEG score recompute
  28. 2026-09-11 22:05 UTCEG score recompute
  29. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  30. 2026-09-10 22:58 UTCEG score recompute
  31. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  32. 2026-09-09 23:52 UTCEG score recompute
  33. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  34. 2026-09-07 21:18 UTCEG score recompute
  35. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  36. 2026-09-06 22:11 UTCEG score recompute
  37. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  38. 2026-09-05 23:04 UTCEG score recompute
  39. 2026-09-04 23:58 UTCEG score recompute
  40. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  41. 2026-09-03 01:44 UTCEG score recompute
  42. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  43. 2026-09-02 02:37 UTCEG score recompute
  44. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  45. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  46. 2026-09-01 03:29 UTCEG score recompute
  47. 2026-09-01 02:41 UTCEG score recompute
  48. 2026-08-30 21:38 UTCEG score recompute
  49. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  50. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  51. 2026-08-28 23:24 UTCEG score recompute
  52. 2026-08-28 22:48 UTCEG score recomputeFirst assessed: 5.9 MEDIUM
  53. 2026-08-28 22:48 UTCMITRE cvelistV5first tracked

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Same product

3 shown

Maven:org.mariadb.jdbc:mariadb-java-client

Frequently asked(5)

What is CVE-2026-55858?
CVE-2026-55858 is a medium-severity vulnerability; its CVE record was published on August 28, 2026. MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, the connector encodes and decodes protocol text and performs client-side escaping under the assumption that the connection character set is UTF-8. The…
When was the CVE record for CVE-2026-55858 published?
The CVE record for CVE-2026-55858 was published on August 28, 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 September 8, 2026; the record at its source may have been updated since.
Is CVE-2026-55858 actively exploited?
CVE-2026-55858 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.9% probability of exploitation in the next 30 days (57th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55858?
CVE-2026-55858 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55858?
A fix for CVE-2026-55858 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55858 are linked in the Vendor Advisories panel on this page.

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