How severe is CVE-2023-26556?

CVE-2023-26556 has a CVSS 3.x base score of 9.1, 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 none.

Is CVE-2023-26556 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-26556?

CVE-2023-26556 affects Iofinnet Tss-lib. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-26556?

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-2023-26556 published?

CVE-2023-26556 was published on 2023-04-21 and last updated on 2026-06-17.

CVE-2023-26556

CVE-2023-26556 is a critical-severity vulnerability in Iofinnet Tss-lib with a CVSS 3.x base score of 9.1. 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-203.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-203
Affected product: Iofinnet Tss-lib
Published: 2023-04-21
Last modified: 2026-06-17

Description

io.finnet tss-lib before 2.0.0 can leak a secret key via a timing side-channel attack because it relies on the scalar-multiplication implementation in Go crypto/elliptic, which is not constant time (there is an if statement in a loop). One leak is in ecdsa/keygen/round_2.go. (bnb-chain/tss-lib and thorchain/tss are also affected.)

Frequently asked questions

What is CVE-2023-26556?: io.finnet tss-lib before 2.0.0 can leak a secret key via a timing side-channel attack because it relies on the scalar-multiplication implementation in Go crypto/elliptic, which is not constant time (there is an if statement in a loop). One leak is in ecdsa/keygen/round_2.go. (bnb-chain/tss-lib and thorchain/tss are also affected.)
How severe is CVE-2023-26556?: CVE-2023-26556 has a CVSS 3.x base score of 9.1, 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 none.
Is CVE-2023-26556 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-26556?: CVE-2023-26556 affects Iofinnet Tss-lib. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-26556?: 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-2023-26556 published?: CVE-2023-26556 was published on 2023-04-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:iofinnet:tss-lib:*:*:*:*:*:*:*:*

More vulnerabilities in Iofinnet Tss-lib

CVE-2022-47931 — Critical (CVSS 9.1): IO FinNet tss-lib before 2.0.0 allows a collision of hash values.
CVE-2023-26557 — High (CVSS 7.5): io.finnet tss-lib before 2.0.0 can leak the lambda value of a private key via a timing side-channel attack because it…
CVE-2022-47930 — Medium (CVSS 6.8): An issue was discovered in IO FinNet tss-lib before 2.0.0. The parameter ssid for defining a session id is not used…

All CVEs affecting Iofinnet Tss-lib →

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Browse all CWE-203 (Observable Discrepancy) vulnerabilities →