How severe is CVE-2020-26547?

CVE-2020-26547 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-2020-26547 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-26547?

CVE-2020-26547 affects Monal. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-26547?

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-2020-26547 published?

CVE-2020-26547 was published on 2021-02-01 and last updated on 2026-06-17.

CVE-2020-26547

CVE-2020-26547 is a critical-severity vulnerability in Monal 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-345.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 5.0
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-345
Affected product: Monal
Published: 2021-02-01
Last modified: 2026-06-17

Description

Monal before 4.9 does not implement proper sender verification on MAM and Message Carbon (XEP-0280) results. This allows a remote attacker (able to send stanzas to a victim) to inject arbitrary messages into the local history, with full control over the sender and receiver displayed to the victim.

Frequently asked questions

What is CVE-2020-26547?: Monal before 4.9 does not implement proper sender verification on MAM and Message Carbon (XEP-0280) results. This allows a remote attacker (able to send stanzas to a victim) to inject arbitrary messages into the local history, with full control over the sender and receiver displayed to the victim.
How severe is CVE-2020-26547?: CVE-2020-26547 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-2020-26547 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-26547?: CVE-2020-26547 affects Monal. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-26547?: 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-2020-26547 published?: CVE-2020-26547 was published on 2021-02-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:monal:monal:*:*:*:*:*:iphone_os:*:*

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