How severe is CVE-2021-26827?

CVE-2021-26827 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-26827 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26827?

CVE-2021-26827 affects Tp-link Tl-wr2041+ Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26827?

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.

When was CVE-2021-26827 published?

CVE-2021-26827 was published on 2021-04-14 and last updated on 2026-06-17.

CVE-2021-26827

CVE-2021-26827 is a high-severity vulnerability in Tp-link Tl-wr2041+ Firmware with a CVSS 3.x base score of 7.5. 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 7.5)
CVSS v2: 7.8
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Tp-link Tl-wr2041+ Firmware
Published: 2021-04-14
Last modified: 2026-06-17

Description

Buffer Overflow in TP-Link WR2041 v1 firmware for the TL-WR2041+ router allows remote attackers to cause a Denial-of-Service (DoS) by sending an HTTP request with a very long "ssid" parameter to the "/userRpm/popupSiteSurveyRpm.html" webpage, which crashes the router.

Frequently asked questions

What is CVE-2021-26827?: Buffer Overflow in TP-Link WR2041 v1 firmware for the TL-WR2041+ router allows remote attackers to cause a Denial-of-Service (DoS) by sending an HTTP request with a very long "ssid" parameter to the "/userRpm/popupSiteSurveyRpm.html" webpage, which crashes the router.
How severe is CVE-2021-26827?: CVE-2021-26827 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-26827 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26827?: CVE-2021-26827 affects Tp-link Tl-wr2041+ Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26827?: 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.
When was CVE-2021-26827 published?: CVE-2021-26827 was published on 2021-04-14 and last updated on 2026-06-17.

References

https://github.com/GD008/vuln/blob/main/tplink_wr2041/tplink_WR2041pv1.md

Affected products (1)

cpe:2.3:o:tp-link:tl-wr2041\+_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 →