CVE-2021-26530
CVE-2021-26530 is a critical-severity vulnerability in Cesanta Mongoose with a CVSS 3.x base score of 9.1. 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-787.
Key facts
- Severity: Critical (CVSS 3.x base score 9.1)
- CVSS v2: 6.4
- EPSS exploit prediction: 1% (70th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Cesanta Mongoose
- Published:
- Last modified:
Description
The mg_tls_init function in Cesanta Mongoose HTTPS server 7.0 (compiled with OpenSSL support) is vulnerable to remote OOB write attack via connection request after exhausting memory pool.
Frequently asked questions
- What is CVE-2021-26530?
- The mg_tls_init function in Cesanta Mongoose HTTPS server 7.0 (compiled with OpenSSL support) is vulnerable to remote OOB write attack via connection request after exhausting memory pool.
- How severe is CVE-2021-26530?
- CVE-2021-26530 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
- Is CVE-2021-26530 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-26530?
- CVE-2021-26530 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-26530?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2021-26530 published?
- CVE-2021-26530 was published on 2021-02-08 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:cesanta:mongoose:7.0:*:*:*:*:*:*:*
More vulnerabilities in Cesanta Mongoose
- CVE-2022-25299 — Critical (CVSS 9.8): This affects the package cesanta/mongoose before 7.6. The unsafe handling of file names during upload using…
- CVE-2020-25756 — Critical (CVSS 9.8): A buffer overflow vulnerability exists in the mg_get_http_header function in Cesanta Mongoose 6.18 due to a lack of…
- CVE-2019-19307 — Critical (CVSS 9.8): An integer overflow in parse_mqtt in mongoose.c in Cesanta Mongoose 6.16 allows an attacker to achieve remote DoS…
- CVE-2019-12951 — Critical (CVSS 9.8): An issue was discovered in Mongoose before 6.15. The parse_mqtt() function in mg_mqtt.c has a critical heap-based…
- CVE-2018-20356 — Critical (CVSS 9.8): An invalid read of 8 bytes due to a use-after-free vulnerability in the mg_http_free_proto_data_cgi function call in…
- CVE-2018-20355 — Critical (CVSS 9.8): An invalid write of 8 bytes due to a use-after-free vulnerability in the mg_http_free_proto_data_cgi function call in…
All CVEs affecting Cesanta Mongoose →
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