CVE-2026-21639
CVE-2026-21639 is a high-severity vulnerability in Ui Airmax Ac Firmware with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- EPSS exploit prediction: 0% (30th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-1493
- Weakness: CWE-120
- Affected product: Ui Airmax Ac Firmware
- Published:
- Last modified:
Description
A malicious actor in Wi-Fi range of the affected product could leverage a vulnerability in the airMAX Wireless Protocol to achieve a remote code execution (RCE) within the affected product.
Frequently asked questions
- What is CVE-2026-21639?
- A malicious actor in Wi-Fi range of the affected product could leverage a vulnerability in the airMAX Wireless Protocol to achieve a remote code execution (RCE) within the affected product.
- How severe is CVE-2026-21639?
- CVE-2026-21639 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-21639 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-21639?
- CVE-2026-21639 primarily affects Ui Airmax Ac Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-21639?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-21639 have an EU (EUVD) identifier?
- Yes. CVE-2026-21639 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1493.
- When was CVE-2026-21639 published?
- CVE-2026-21639 was published on 2026-01-08 and last updated on 2026-07-30.
References
Affected products (4)
- cpe:2.3:o:ui:airmax_ac_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:ui:airmax_m_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:ui:airfiber_af60-xg_firmware:*:*:*:*:*:*:*:*
- cpe:2.3:o:ui:airfiber_af60_firmware:*:*:*:*:*:*:*:*
More vulnerabilities in Ui Airmax Ac Firmware
- CVE-2015-9266 — Critical (CVSS 9.8): The web management interface of Ubiquiti airMAX, airFiber, airGateway and EdgeSwitch XP (formerly TOUGHSwitch) allows…
- CVE-2022-44565 — Medium (CVSS 5.3): An improper access validation vulnerability exists in airMAX AC <8.7.11, airFiber 60/LR <2.6.2, airFiber 60 XG/HD…
All CVEs affecting Ui Airmax Ac Firmware →
Other CWE-120 (Classic Buffer Overflow) vulnerabilities
- CVE-2025-48611 — Critical (CVSS 10.0): In DeviceId of DeviceId.java, there is a possible desync in persistence due to a missing bounds check. This could lead…
- CVE-2026-24823 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in FASTSHIFT…
- CVE-2026-24810 — Critical (CVSS 10.0): Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in rethinkdb (src/cjson modules).…
- CVE-2026-24800 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in tildearrow…
- CVE-2025-9962 — Critical (CVSS 10.0): A buffer overflow vulnerability in Novakon P series allows attackers to gain root permission without prior…
- CVE-2010-10016 — Critical (CVSS 10.0): BS.Player version 2.57 (build 1051) contains a vulnerability in its playlist import functionality. When processing .m3u…
Browse all CWE-120 (Classic Buffer Overflow) vulnerabilities →