How severe is CVE-2021-33304?

CVE-2021-33304 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-33304 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-2021-33304?

CVE-2021-33304 primarily affects Altran Picotcp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-33304?

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-2021-33304 published?

CVE-2021-33304 was published on 2023-02-15 and last updated on 2026-06-17.

CVE-2021-33304

CVE-2021-33304 is a critical-severity vulnerability in Altran Picotcp with a CVSS 3.x base score of 9.8. 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-415.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-415
Affected product: Altran Picotcp
Published: 2023-02-15
Last modified: 2026-06-17

Description

Double Free vulnerability in virtualsquare picoTCP v1.7.0 and picoTCP-NG v2.1 in modules/pico_fragments.c in function pico_fragments_reassemble, allows attackers to execute arbitrary code.

Frequently asked questions

What is CVE-2021-33304?: Double Free vulnerability in virtualsquare picoTCP v1.7.0 and picoTCP-NG v2.1 in modules/pico_fragments.c in function pico_fragments_reassemble, allows attackers to execute arbitrary code.
How severe is CVE-2021-33304?: CVE-2021-33304 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-33304 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-2021-33304?: CVE-2021-33304 primarily affects Altran Picotcp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-33304?: 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-2021-33304 published?: CVE-2021-33304 was published on 2023-02-15 and last updated on 2026-06-17.

References

https://github.com/virtualsquare/picotcp/issues/6

Affected products (2)

cpe:2.3:a:altran:picotcp:1.7.0:*:*:*:*:*:*:*
cpe:2.3:a:altran:picotcp-ng:2.1:*:*:*:*:*:*:*

More vulnerabilities in Altran Picotcp

CVE-2020-24338 — Critical (CVSS 9.8): An issue was discovered in picoTCP through 1.7.0. The DNS domain name record decompression functionality in…
CVE-2017-1000210 — Critical (CVSS 9.8): picoTCP (versions 1.7.0 - 1.5.0) is vulnerable to stack buffer overflow resulting in code execution or denial of…
CVE-2020-24341 — Critical (CVSS 9.1): An issue was discovered in picoTCP and picoTCP-NG through 1.7.0. The TCP input data processing function in pico_tcp.c…
CVE-2020-17441 — Critical (CVSS 9.1): An issue was discovered in picoTCP 1.7.0. The code for processing the IPv6 headers does not validate whether the IPv6…
CVE-2023-30463 — High (CVSS 7.5): Altran picoTCP through 1.7.0 allows memory corruption (and subsequent denial of service) because of an integer overflow…
CVE-2020-24340 — High (CVSS 7.5): An issue was discovered in picoTCP and picoTCP-NG through 1.7.0. The code that processes DNS responses in…

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CVE-2020-37239 — Critical (CVSS 9.8): libbabl 0.1.62 contains a broken double free detection vulnerability that allows attackers to bypass memory safety…
CVE-2026-43011 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix potential double free of skb When…
CVE-2026-31609 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid double-free in…
CVE-2026-31608 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: server: avoid double-free in…

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