The CBSE on Tuesday said that "malicious actors" targeted its re-evaluation portal with a series of cyberattacks, including a denial-of-service (DoS) attack that generated 1.5 million hits within two minutes and over one lakh attempts at unauthorised file access.
The board said the portal is currently supporting over 8,000 concurrent users and that more than 16,000 students had successfully completed their submissions as of 3 pm.
"While thousands of students accessed the CBSE re-evaluation portal today, malicious actors attempted to disrupt services through a barrage of cyberattacks," the board said in a post on X.
"The most recent being a denial of service attack attempt causing 1.5 million hits on the portal within a matter of two minutes and more than one lakh attempts of unauthorised file access," it added.
Based on student feedback, the CBSE said it has further refined the platform, including extending session time limits, to make the process more convenient and seamless.
"Our teams remain vigilant and responsive to ensure our dearest students are facilitated in all ways possible," the board said.
Earlier in the day, the CBSE opened its online portal for verification of issues in scanned copies of answer books and re-evaluation of answers for students dissatisfied with their board exam evaluation.
According to the board, the facility is available only to students who have obtained scanned copies of their evaluated answer books.
"The portal for applying for verification of issues observed in supplied scanned copy of answer book and re-evaluation of answers has been made live on June 2, 2026. Students can avail the facility of verification of issue(s) observed in supplied scanned copy of answer book, if any, and re-evaluation of answer(s) if not satisfied with the evaluation," the CBSE said.
The portal will remain open from June 2 to June 6 (midnight), and no offline applications or requests submitted after the deadline will be accepted.
Students are required to log in through the CBSE website using their Aadhaar number and submit applications online. The entire process, including fee payment, will be conducted digitally.
For verification of issues in scanned copies of answer books, students can report concerns such as missing pages, missing supplementary sheets, missing maps or graphs, blurred pages, incorrect answer books or evaluation against a different question paper set.
"Students are advised to ensure that all requests across subjects are included before final submission," the board said.
The fee for verification of issues in scanned answer books is Rs 100 per answer book, while re-evaluation of answers will cost Rs 25 per question.
Payments can be made only through online modes such as UPI, credit card, debit card and net banking.
"Students may submit only one application each for verification of issues/re-evaluation and are therefore advised to decide in advance whether to apply for one or multiple subjects," the board said.
The CBSE added that once the "Freeze and Proceed to Payment" button is clicked, the details will be locked and cannot be edited. Students have therefore been advised to verify all details carefully before submission.
Applications will be considered successfully submitted only after completion of online payment.
The board also clarified that only one application each for verification of issues and re-evaluation will be permitted.
"Students may also apply online for re-evaluation of one or more questions across one or more subjects by providing the required details, including question number and page number, as the case may be," it said.
The CBSE said the outcome of the requests would be communicated after completion of the process and urged candidates to submit their applications within the prescribed timeline.
A visual guide and tutorial video have also been made available to assist students with the process.
The board further said Aadhaar-based verification has been introduced for security reasons while applying for verification of issues and re-evaluation of answers.
"For children who do not have Aadhaar, the parent's, relative's or guardian's Aadhaar details may be used," the board said.
"In this case, the Aadhaar name, date of birth and gender must be of the person whose Aadhaar number is used," it added.
The portal was launched after a delay, with the CBSE earlier stating that applications for verification and re-evaluation were expected to begin by May 29.
The development comes amid concerns raised by some students and parents regarding the On-Screen Marking (OSM) system. The board has faced criticism over technical glitches, payment failures and access-related issues during the verification and re-evaluation process.
(With inputs from PTI)