How severe is CVE-2021-39532?

CVE-2021-39532 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-39532 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39532?

CVE-2021-39532 affects Juniper Libslax. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39532?

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

When was CVE-2021-39532 published?

CVE-2021-39532 was published on 2021-09-20 and last updated on 2026-06-17.

CVE-2021-39532

CVE-2021-39532 is a medium-severity vulnerability in Juniper Libslax 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Juniper Libslax
Published: 2021-09-20
Last modified: 2026-06-17

Description

An issue was discovered in libslax through v0.22.1. A NULL pointer dereference exists in the function slaxLexer() located in slaxlexer.c. It allows an attacker to cause Denial of Service.

Frequently asked questions

What is CVE-2021-39532?: An issue was discovered in libslax through v0.22.1. A NULL pointer dereference exists in the function slaxLexer() located in slaxlexer.c. It allows an attacker to cause Denial of Service.
How severe is CVE-2021-39532?: CVE-2021-39532 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-39532 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39532?: CVE-2021-39532 affects Juniper Libslax. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39532?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39532 published?: CVE-2021-39532 was published on 2021-09-20 and last updated on 2026-06-17.

References

https://github.com/Juniper/libslax/issues/50

Affected products (1)

cpe:2.3:a:juniper:libslax:*:*:*:*:*:*:*:*

More vulnerabilities in Juniper Libslax

CVE-2021-39534 — High (CVSS 8.8): An issue was discovered in libslax through v0.22.1. slaxIsCommentStart() in slaxlexer.c has a heap-based buffer…
CVE-2021-39533 — High (CVSS 8.8): An issue was discovered in libslax through v0.22.1. slaxLexer() in slaxlexer.c has a heap-based buffer overflow.
CVE-2021-39531 — High (CVSS 8.8): An issue was discovered in libslax through v0.22.1. slaxLexer() in slaxlexer.c has a stack-based buffer overflow.
CVE-2019-1010232 — Medium (CVSS 6.5): Juniper juniper/libslax libslax latest version (as of commit 084ddf6ab4a55b59dfa9a53f9c5f14d192c4f8e5 Commits on Sep 1,…

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