CVE-2026-76834

HIGHPre-NVD 8.18.1—
EchelonGraph scoreHIGH confidence

Score 8.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-17. a secondary CVSS source baseline 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

b2evolution CMS versions 6.7.8 through 7.2.5 contain an incomplete fix for CVE-2016-8901 where the serialized-array object check in param_check_serialized_array() fails to reject payloads with negative integer array keys. Unauthenticated attackers can submit crafted serialized PHP objects via POST requests to htsrv/call_plugin.php that bypass validation and reach unserialize(), instantiating arbitrary PHP objects with attacker-chosen properties that may enable code execution if suitable POP gadget chains exist.

CVSS v3
8.1
EG Score
8.1(high)
EG Risk
37(Track)
EG Risk 37/100SSVC: Track

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
Severity81% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
57%
KEV
Not listed

Published

September 17, 2026

Last Modified

September 18, 2026

Advisory Details (8)

Auto-updated Sep 17, 2026
Patch available. Sources: github_commit.
generic

b2evolution CMS 6.7.8 through 7.2.5 Object Injection via Negative Integer Array Key | Advisories | VulnCheck

https://www.vulncheck.com/advisories/b2evolution-cms-6.7.8-through-7.2.5-object-injection-via-negative-integer-array-key
generic

GitHub - b2evolution/b2evolution: b2evolution CMS: Multiblog/CMS content publishing + forums + email marketing + social network + more... b2evolution includes everything you need to run and maintain a modern website. Optimized for low maintenance with easy upgrades and effective antispam. Full RWD & bootstrap support. · GitHub

https://github.com/b2evolution/b2evolution
github_commit Patch Available

commit 335abf09bcea (b2evolution/b2evolution)

Patch available: b2evolution/b2evolution 6-9-4 (contains commit 335abf09bcea)

https://github.com/b2evolution/b2evolution/commit/335abf09bcea61717bd00bc1e3889f8100ebd1bb
github_commit Patch Available

commit 999b5ad1d597 (b2evolution/b2evolution)

Patch available: b2evolution/b2evolution 6-9-4 (contains commit 999b5ad1d597)

https://github.com/b2evolution/b2evolution/commit/999b5ad1d59760d7e450ceb541f55432fc74cd27
github_commit Patch Available

commit 25c21cf9cc42 (b2evolution/b2evolution)

Patch available: b2evolution/b2evolution 6-9-4 (contains commit 25c21cf9cc42)

https://github.com/b2evolution/b2evolution/commit/25c21cf9cc4261324001f9039509710b37ee2c4d
generic

b2evolution/htsrv/call_plugin.php at 7.2.5 · b2evolution/b2evolution · GitHub

https://github.com/b2evolution/b2evolution/blob/7.2.5/htsrv/call_plugin.php#L49
generic

b2evolution/inc/_core/_param.funcs.php at 7.2.5 · b2evolution/b2evolution · GitHub

https://github.com/b2evolution/b2evolution/blob/7.2.5/inc/_core/_param.funcs.php#L2860
generic

CVE-2026-76834 — PHP Object Injection in b2evolution CMS (Incomplete Fix of CVE-2016-8901) · GitHub

https://gist.github.com/axg11/3e29501c33f6e1e05ac2a00107afd64e

Vendor Advisories for CVE-2026-76834(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 18× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-09-20 22:03 UTCEG score recompute
  2. 2026-09-20 22:03 UTCGHSA enrichment
  3. 2026-09-20 20:16 UTCEPSS rescore
  4. 2026-09-20 09:10 UTCGHSA enrichment
  5. 2026-09-19 20:17 UTCEG score recompute
  6. 2026-09-19 20:17 UTCGHSA enrichment
  7. 2026-09-19 07:24 UTCEG score recompute
  8. 2026-09-19 07:24 UTCGHSA enrichment
  9. 2026-09-18 19:28 UTCEPSS rescore
  10. 2026-09-18 18:31 UTCEG score recompute
  11. 2026-09-18 18:31 UTCGHSA enrichment
  12. 2026-09-18 18:15 UTCEG score recompute
  13. 2026-09-18 18:15 UTCGHSA enrichment
  14. 2026-09-18 06:50 UTCEG score recompute
  15. 2026-09-18 06:50 UTCGHSA enrichment
  16. 2026-09-17 17:57 UTCEG score recompute
  17. 2026-09-17 15:25 UTCEG score recompute
  18. 2026-09-17 15:24 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-76834?
CVE-2026-76834 is a high vulnerability published on September 17, 2026. b2evolution CMS versions 6.7.8 through 7.2.5 contain an incomplete fix for CVE-2016-8901 where the serialized-array object check in paramcheckserializedarray() fails to reject payloads with negative integer array keys. Unauthenticated attackers can submit crafted serialized PHP objects via POST…
When was CVE-2026-76834 disclosed?
CVE-2026-76834 was first published in the National Vulnerability Database on September 17, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76834 actively exploited?
CVE-2026-76834 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 43.5% of all scored CVEs.
What is the CVSS score of CVE-2026-76834?
CVE-2026-76834 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-76834?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76834, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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