CVE-2026-55005: Heap-based buffer overflow in Microsoft Exchange Server allows an authorized attacker to execute code over a network.

highCVSS 8.8CVE-2026-55005

Heap-based buffer overflow in Microsoft Exchange Server allows an authorized attacker to execute code over a network.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 8.8
Published: 2026-07-14
Last updated: 2026-07-15
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-55005

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-550050.66% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 48% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-55005	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[NEW] [high] Microsoft Exchange: Multiple vulnerabilitiescert-bund
unknownNCSC-2026-0234 [1.00] [M/H] Vulnerabilities fixed in Microsoft Exchangencsc-nl
highCVE-2026-55005: Microsoft Exchange Server Remote Code Execution Vulnerabilitymsrc

Recent advisories for Heap-based buffer overflow

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-13307: Autel MaxiCharger AC Elite Home USB Heap-based Buffer Overflow Arbitrary Code Execution Vulner…nvd · 2026-07-29
highCVE-2026-14266: 7-Zip XZ Decompression Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vu…nvd · 2026-07-29
highCVE-2026-48372: Format Plugins is affected by a Heap-based Buffer Overflow vulnerability that could result in …nvd · 2026-07-28
unknownCVE-2026-17572: Heap-based buffer overflow in the SOHM list-index deserialization code in HDF5 through 2.1.1 o…nvd · 2026-07-27
criticalCVE-2026-55971: Heap-based Buffer Overflow vulnerability in Apache Thrift C++ bindings. This issue affects Apa…nvd · 2026-07-27
highCVE-2026-66374: Knot Resolver before 6.4.1 allows remote code execution via a heap-based buffer overflow in th…nvd · 2026-07-25