How severe is CVE-2021-31878?

CVE-2021-31878 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-31878 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31878?

CVE-2021-31878 primarily affects Digium Asterisk. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31878?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-31878 published?

CVE-2021-31878 was published on 2021-07-30 and last updated on 2026-06-17.

CVE-2021-31878

CVE-2021-31878 is a medium-severity vulnerability in Digium Asterisk with a CVSS 3.x base score of 6.5. 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-617.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-617
Affected product: Digium Asterisk
Published: 2021-07-30
Last modified: 2026-06-17

Description

An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.

Frequently asked questions

What is CVE-2021-31878?: An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1. To exploit, a re-INVITE without SDP must be received after Asterisk has sent a BYE request.
How severe is CVE-2021-31878?: CVE-2021-31878 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-31878 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31878?: CVE-2021-31878 primarily affects Digium Asterisk. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31878?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-31878 published?: CVE-2021-31878 was published on 2021-07-30 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:digium:asterisk:16.17.0:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:16.18.0:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:16.19.0:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:18.3.0:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:18.4.0:*:*:*:*:*:*:*
cpe:2.3:a:digium:asterisk:18.5.0:*:*:*:*:*:*:*

More vulnerabilities in Digium Asterisk

CVE-2022-26651 — Critical (CVSS 9.8): An issue was discovered in Asterisk through 19.x and Certified Asterisk through 16.8-cert13. The func_odbc module…
CVE-2017-14100 — Critical (CVSS 9.8): In Asterisk 11.x before 11.25.2, 13.x before 13.17.1, and 14.x before 14.6.1 and Certified Asterisk 11.x before…
CVE-2022-26499 — Critical (CVSS 9.1): An SSRF issue was discovered in Asterisk through 19.x. When using STIR/SHAKEN, it's possible to send arbitrary requests…
CVE-2014-8418 — Critical (CVSS 9.0): The DB dialplan function in Asterisk Open Source 1.8.x before 1.8.32, 11.x before 11.1.4.1, 12.x before 12.7.1, and…
CVE-2011-1599 — Critical (CVSS 9.0): manager.c in the Manager Interface in Asterisk Open Source 1.4.x before 1.4.40.1, 1.6.1.x before 1.6.1.25, 1.6.2.x…
CVE-2019-18610 — High (CVSS 8.8): An issue was discovered in manager.c in Sangoma Asterisk through 13.x, 16.x, 17.x and Certified Asterisk 13.21 through…

All CVEs affecting Digium Asterisk →

Other CWE-617 (Reachable Assertion) vulnerabilities

CVE-2020-3615 — Critical (CVSS 9.8): Valid deauth/disassoc frames is dropped in case if RMF is enabled and some rouge peer keep on sending rogue…
CVE-2019-9795 — Critical (CVSS 9.8): A vulnerability where type-confusion in the IonMonkey just-in-time (JIT) compiler could potentially be used by…
CVE-2026-31739 — High (CVSS 8.8): In the Linux kernel, the following vulnerability has been resolved: crypto: tegra - Add missing CRYPTO_ALG_ASYNC The…
CVE-2020-12417 — High (CVSS 8.8): Due to confusion about ValueTags on JavaScript Objects, an object may pass through the type barrier, resulting in…
CVE-2020-6623 — High (CVSS 8.8): stb stb_truetype.h through 1.22 has an assertion failure in stbtt__cff_get_index.
CVE-2020-6619 — High (CVSS 8.8): stb stb_truetype.h through 1.22 has an assertion failure in stbtt__buf_seek.

Browse all CWE-617 (Reachable Assertion) vulnerabilities →