8.7

CVE-2026-40618: f5 big-ip Incorrect Calculation of Buffer Size

CVSS: 8.7v4.0HighAnalyzed
Published 13-05-2026Last modified 13-05-2026
Open JSON

Vulnerability summary

CVE-2026-40618 is a high (CVSS 8.7) Incorrect Calculation of Buffer Size vulnerability in f5 big-ip. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.5% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.46%
0%100%
Low · +0.14 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 13-05-2026
    PublishedVulnerability first disclosed.
  2. 13-05-2026
    Last modifiedVulnerability information updated.

Description

When an SSL profile is configured on a virtual server on BIG-IP Virtual Edition (VE) without Intel QuickAssist Technology (QAT) or on BIG-IP hardware platforms with the database variable crypto.hwacceleration set to disabled, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.46%

Chance of exploitation in the next 30 days

Percentile

39%

Versus all other CVEs

30-day change

+0.14 pp

From 0.32% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.46%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

F527 products

1 vendor · 27 products

References

1 links