The TCP Server module in toxcore before 0.2.8 doesn't free the TCP priority queue under certain conditions, which allows a remote attacker to exhaust the system's memory, causing a denial of service (DoS).
Conclusion & alert: CVE-2018-25021 is rated High Exploit Risk (74.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.27%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.29% over the last day, indicating growing attacker interest. Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.98% | 2.27% | +1.29% |
| 2 | 2025-03-30 | 1.44% | 0.98% | -0.46% |
| 3 | 2025-03-29 | — | 1.44% | — |
Full EPSS history (14 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2018-25021 not yet assigned priority: Debian including 1 source packages (libtoxcore), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2018-25021 |
ubuntu
|
medium | CVE-2018-25021 medium priority: Ubuntu including 1 source packages (libtoxcore), 7 status rows across 7 suites (bionic, focal, jammy, kinetic, trusty, upstream, xenial): not-affected 3, ignored 2, DNE 1, released 1. | https://ubuntu.com/security/CVE-2018-25021 |
| URL | Tags |
|---|---|
| https://blog.tox.chat/2018/10/memory-leak-bug-and-new-toxcore-release-fixing-it/ | Third Party Advisory |
| https://github.com/TokTok/c-toxcore/issues/1214 | Exploit Third Party Advisory |
| https://github.com/TokTok/c-toxcore/pull/1216 | Third Party Advisory |